Dipole-Dipole and Ion-Dipole Interactions偶极与离子-偶极相互作用
CHAPTER 3 CHEMICAL BONDING 化学键
STRUCTURE AND BONDING
The physical properties of a substance depend on its structure and type of bonding present. Bonding determines the type of structure.
• Co-ordinate (dative covalent) bonding
• Molecular solids • Covalent networks • Metallic bonding
STRUCTURE AND BONDING
The physical properties of a substance depend on its structure and type of bonding present. Bonding determines the type of structure.
THE IONIC BOND
Ionic bonds tend to be formed between elements whose atoms need to “lose” electrons to gain the nearest noble gas electronic configuration (n.g.e.c.) and those which need to gain electrons. The electrons are transferred from one atom to the other. Sodium Chloride
IBChemistry
The Octet Rule
• Atoms tend to gain, lose, or share e- until they are surrounded by 8 valence e- and are thus energetically stable.
• Exceptions do occur (and will be discussed later.)
2
Valence Electrons
• Valence electrons are the electrons in the outer shell that are on the same period or row. These are the electrons that are involved in bonding atoms together.
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
– Ionic compounds are neutral, the positive charges balance out the negative charges.
– Ionic bonds form a lattice structure
20
Ionic Bonding
• Results as atoms lose or gain e- to achieve 8 electrons in the highest shell
Fluorescence Resonance Energy Transfer (FRET)荧光共振能量转移(FRET)
(H3C)2N
• chemical attachment of synthetic dyes
O
N+(CH3)2
OCH3 O
R
Absorption / Emission (a.u.)
580
fluorescence
a typical synthetic chromophore: tetramethylrhodamine
Absorption Emission
400 450 500 550 600 650 700 wavelength (nm)
• extinction coefficient: ~100,000 Molar-1 cm-1 • fluorescence quantum yield: ~50% • triplet quantum yield <1% • available in reactive forms (to attach to amines,
fluorophore *Donor-Acceptor의 Energy transfer는 거리에 의해 효율이 결정 (~10nm)
Spectral properties of involved chromophore
FRET
Calculation
Efficiency of Energy Transfer = E = kT/(kT + kf + k’) kT = rate of transfer of excitation energy kf = rate of fluorescence k’ = sum of the rates of all other deexcitation
fluorescence experiments 4. Some applications & examples
溶液和溶解度
Chapter 3 solutions and solubility溶液和溶解度3.1 Types of Solutions 溶液的类型Ⅰ.Key terms 关键词Solution 溶液Solvent 溶剂Solutes 溶质Concentrated solution 浓溶液Diluted solution 稀溶液Aqueous solution 水溶液Miscible 相溶Immiscible 不相溶Alloys 合金Saturated solution 饱和溶液Unsaturated solution 不饱和溶液II.Topics 知识点·What is solution?A homogeneous mixture of a solvent and one or more solutes. 溶液是由一种溶剂和一种或多种溶质组成的混合物。
·What is solvent?A substance that has other substances dissolved in it.溶剂是其它物质能够溶解在其中的物质。
·What is solute?A substance that is dissolved in a solution.溶质是溶解在溶液中的物质。
·What is concentrated solution?A solution that has a higher proportion of solute to solvent than a dilute solution.浓溶液是溶质与溶剂比例比稀溶液高的溶液。
·What is dilute solution?It has a lower proportion of solute to solvent than a concentrated solution.稀溶液是溶质与溶剂比例比浓溶液低的溶液。
Chapter 11 Intermolecular Forces and Liquids and Solids
Covalent bonding
• Occurs when elements share electrons • Usually occurs between nonmetals
11.2
Intermolecular Forces
Dispersion Forces Attractive forces that arise as a result of temporary dipoles induced in atoms or molecules The separation of the negative and positive charges in a nonpolar molecule is due to the proximity of an ion or a polar molecule
Intermolecular Forces and Liquids and Solids
Chapter 11
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
States of Matter
• The strength of dispersion forces tends to increase with increased molecular weight. • Larger atoms have larger electron clouds, which are easier to polarize.
alevel化学常用单词汇总
ｃh ａp ｔer １ atomic st ｒuctureｅlement n.元素all know ｍａteri ａl ｓ ca ｎ be bro ｋｅn ｄｏwn in ｔo fundamental sub ｓｔances we c ａll ｅlem ｅnt.我们所知道的所有物质都可以分解成原子。
ａｔo ｍ n.原子ato ｍ is t ｈe smallest p ａr ｔic ｌe o ｆ ｍatter ｈa ｖin ｇ ａｌl tha ｔ ele ｍent ’s c ｈarac ｔer ｉs ｔic ｓ.原子时具有元素性质的最小粒子。
nucleu ｓ /’nj ｕ:kl ｉəｓ,’n ｕːｋli əs/ 原子核e ｌｅc ｔron ｎ.电子prot ｏn 质子 n ｅut ｒon 中子compoun ｄ ｎ． 化合物：Wh ｅn two or ｍore elemen ｔs combine ａnd f ｏｒm a compo ｕnd, a chem ｉｃal change t ａkes p ｌace.当两种或两种以上的元素结合形成化合物时, 发生化学变化。
atom nucleus election proton neutron {{(+)(-)化学中的物质分为单质和化合物,大部分元素是以化合物的形式存在的。
ion n.离子：when an atom gｅｔoｒlｏsｔeleｃtｉoｎｓ,iｔbｅcoｍｅs ion．原子得失电子后形成离子。
ｃaｔhode n. 阴极（ｎegative ｅlｅcｔｒｏｄe)Ｃａtｈode ｒays aｒe ａttractｅd by ａposｉtiｖｅcharge．阴极射线被阳电荷所吸引。
anode ｎ. 阳极(positive eｌectｉｏn)A red wｉｒe is oｆｔeｎattached to tｈe anode．红色电线通常与阳极相联。
paｒticlｅn. 粒子：Pａrticｌes include ｍoleculars,atｏmｓ, ｐｒotｏns, neutrons ，electrons anｄｉons.微小粒子包括分子，原子，质子,中子,电子，离子等等。
Dipole-Dipole and Ion-Dipole Interactions偶极与离子-偶极相互作用
Dipole-Dipole Forces
• When polar molecules come in contact with each other
• partially positive end of a molecule is attracted to a partially negative end and vice-versa.
Check it Out!
• sumanasinc/webcontent/animations/content/propertiesofwat er/water.html
Comparison
Similarities
• Both interactions are between a positively charged end of a molecule with a negatively charged end of a molecule
Ion-Dipole Forces
• between an ion and a polar molecule
• cations are attracted to the partially negative ends of a neutral polar molecule, while anions are attracted to the partially positive ends of a neutral polar molecule
attracted to the partially negative oxygen. This is also considered a hydrogen bond, because the force of attraction between the
Dipole-Dipole and Ion-Dipole Interactions偶极与离子-偶极相互作用
Bibliography
• /genchem/topicreview/bp/intermol/intermol.html#for ce
• /gchelp/liquids/dipdip.html • abeliaschemistry.spot/p/dipole-dipole-forces.html • sumanasinc/webcontent/animations/content/propertiesofwater/water.html • /chem/senese/101/liquids/faq/h-bonding-vs-london-
Ion-Dipole Forces
• between an ion and a polar molecule
• cations are attracted to the partially negative ends of a neutral polar molecule, while anions are attracted to the partially positive ends of a neutral polar molecule
attracted to the partially negative oxygen. This is also considered a hydrogen bond, because the force of attraction between the
hydrogen of one molecule to an electronegative element, which is oxygen.
chemistry glossary
accelerationMeasure of how fast velocity is changing, so we can think of it as thechange in velocity over change in time. The most common use ofacceleration is acceleration due to gravity, which can also appear asthe gravitational constant (9.8 m/s2).acidCompound that gives off H+ ions in solution.acidicDescribes a solution with a high concentration of H+ ions.anionIons with a negative charge.anodeThe electrode where electrons are lost (oxidized) in redox reactions. areaMeasures the size of a surface using length measurements in twodimensions.associativityA property in math which states that: (A+B)+C=A+(B+C) and(A*B)*C=A*(B*C).atmospheresCommon units for measuring pressure.atomThe smallest object that retains properties of an element. Composed of electrons and a nucleus (containing protons and neutrons).atomic numberNumber of protons in an element.Avogadro's numberNumber representing the number of molecules in one (1) mole: 6.022 * 1023.BbaseSubstance which gives off hydroxide ions (OH-) in solution.basicHaving the characteristics of a base.Bohr's atomBohr made significant contributions to the atom. He understood theline spectra-- the reason why only certain wavelengths are emittedwhen atoms jump down levels.buffer solutionsSolutions that resist changes in their pH, even when small amounts of acid or base are added.CcatalystSubstance that speeds up a chemical process without actuallychanging the products of reaction.cathodeElectrode where electrons are gained (reduction) in redox reactions. cationsIon with a positive charge.central atomIn a Lewis structure, usually the atom that is the least electronegative. chargeDescribes an object's ability to repel or attract other objects. Protonshave positive charges while electrons have negative charges. Likecharges repel each other while opposite charges, such as protons andelectrons, attract one another.chemical changesProcesses or events that have altered the fundamental structure ofsomething.chemical equationAn expression of a fundamental change in the chemical substances. closureA mathematical term which says that if you operated on any two realnumbers A and B with +, -, * or /, you get a real number. colligative propertiesProperties of a solution that depend only on the number of particlesdissolved in it, not the properties of the particles themselves. Themain colligative properties addressed at this web site are boiling point elevation and freezing point depression.combustionWhen substances combine with oxygen and release energy.commutativityA math property which states: A+B=B+A and A*B=B*A. compoundTwo or more atoms joined together chemically, with covalent or ionic bonds.concentrationThe amount of substance in a specified space.conjugate acidA substance which can lose a H+ ion to form a base.conjugate baseA substance which can gain a H+ ion to form an acid.covalent bondsWhen two atoms share at least one pair of electrons.Ddaughter isotopeIn a nuclear equation the compound remaining after the parent isotope (the original isotope) has undergone decay. A compound undergoingdecay, such as alpha decay, will break into an alpha particle and adaughter isotope.decayChange of an element into a different element, usually with someother particle(s) and energy emitted.decimalThe number of digits to the right of the decimal point in a number. denseA compact substance or a substance with a high density.densityMass per unit volume of a substance.dipole-dipole forcesIntermolecular forces that exist between polar molecules. Active only when the molecules are close together. The strengths ofintermolecular attractions increase when polarity increases. dispersion forces (also called London dispersion forces)Dispersion is an intermolecular attraction force that exists between all molecules. These forces are the result of the movement of electronswhich cause slight polar moments. Dispersion forces are generallyvery weak but as the molecular mass increases so does their strength. dissociationBreaking down of a compound into its components to form ions from an ionic substance.distributivityA math property which states: A*(B+C)=(A*B)+(A*C).double bondWhen an atom is bonded to another atom by two sets of electron pairs.EeffusionMovement of gas molecules through a small opening. electrochemical cellGives an electric current with a steady voltage as a result of anelectron transfer reaction.electrodesDevice that moves electrons into or out of a solution by conduction. electrolysisChanging the chemical structure of a compound using electricalenergy.electromagnetic spectrumComplete range of wavelengths which light can have. These includeinfrared, ultraviolet, and all other types of electromagnetic radiation,as well as visible light.electronOne of the parts of the atom having a negative charge. Indivisibleparticle with a charge of -1.electron geometryStructure of a compound based on the arrangement of its electrons. electronegativityMeasure of a substance's ability to attract electrons.electrostatic forcesForces between charged objects.elementSubstance consisting of only one type of atom.empirical formulaFormula showing the simplest ratio of elements in a compound. endothermicProcess that absorbs heat from its surroundings as the reactionproceeds.energyAbility to do work.enthalpyChange in heat at constant pressure.entropyMeasure of the disorder of a system.equilibriumWhen the reactants and products are in a constant ratio. The forwardreaction and the reverse reactions occur at the same rate when asystem is in equilibrium.equilibrium constantValue that expresses how far the reaction proceeds before reachingequilibrium. A small number means that the equilibrium is towardsthe reactants side while a large number means that the equilibrium istowards the products side.equilibrium expressionsThe expression giving the ratio between the products and reactants.The equilibrium expression is equal to the concentration of eachproduct raised to its coefficient in a balanced chemical equation andmultiplied together, divided by the concentration of the product ofreactants to the power of their coefficients.equivalence pointOccurs when the moles of acid equal the moles of base in a solution. exothermicProcess that gives off heat to the environment.exponentiationRaising something to a power.FforceAn entity that when applied to a mass causes it to accelerate. Sir Isaac Newton's Second Law of Motion states: the magnitude of aforce=mass*acceleration.free electronElectron which is not attached to a nucleus.frequencyNumber of events in a given unit of time. When describing a movingwave, means the number of peaks which would pass a stationary point in a given amount of time.GGeiger counterInstrument that measures radiation output.Gibb's free energyThe energy of a system that is available to do work at constanttemperature and pressure.Graham's lawThe rate of diffusion of a gas is inversely proportional to the squareroot of its molar mass.Hhalf lifeThe amount of time it takes for half an initial amount to disintegrate. Heisenberg uncertainty principleThis principle states that it is not possible to know a particle's location and momentum precisely at any time.hydrogen bondingStrong type of intermolecular dipole-dipole attraction. Occursbetween hydrogen and F, O or N.hydrolysisThe reactions of cations with water to produce a weak base or ofanions to produce a weak acid.Iideal gas lawPV=nRTDescribes the relationship between pressure (P), temperature (T),volume (V), and moles of gas (n). This equation expresses behaviorapproached by real gases at low pressure and high temperature. identityA math property which states: A+0=A and A*1=A.intermolecular forcesForces between molecules.intramolecular forcesForces within molecules. Forces caused by the attraction andrepulsion of charged particles.inverseA math property which states: A+(-A)=0 and A*(1/A)=1ionRemoving or adding electrons to an atom creates an ion (a chargedobject very similar to an atom).ion-dipole forcesIntermolecular force that exists between charged particles andpartially charged molecules.ionic bondsWhen two oppositely charged atoms share at least one pair ofelectrons but the electrons spend more time near one of the atoms than the other.ionization energyEnergy required to remove an electron from a specific atom.ionizesWhen a substance breaks into its ionic components.isotopesElements with the same number of protons but have different numbers of neutrons, and thus different masses.KKelvinThe SI Unit of temperature. It is the temperature in degrees Celsiusplus 273.15.kinetic energyEnergy an object has because of its mass and velocity. Objects thatnot moving have no kinetic energy. (Kinetic Energy=0.5*mass*velocity2.LLe Chatlier's principleStates that a system at equilibrium will oppose any change in theequilibrium conditions.Lewis structuresA way of representing molecular structures based on valence electrons. limiting reagentThe reactant that will be exhausted first.line spectraSpectra generated by excited substances. Consists of radiation withonly specific wavelengths.Mmass numberThe number of protons and neutrons in an atom.mixtureComposed of two or more substances, but each keeps its originalproperties.molalityThe number of moles of solute (the material dissolved) per kilogramof solvent (what the solute is dissolved in).molarAn term expressing molarity, the number of moles of solute per litersof solution.molarityThe number of moles of solute (the material dissolved) per liter ofsolution. Used to express the concentration of a solution.moleA collection of 6.022* 1023 number of objects. Usually used to meanmolecules.molecular formulaShows the number of atoms of each element present in a molecule. molecular geometryShape of a molecule, based on the relative positions of the atoms. molecular massThe combined mass (as given on the periodic table) of all the elements in a compound.moleculeTwo or more atoms chemically combined.mole fractionThe number of moles of a particular substance expressed as a fraction of the total number of moles.NneutralAn object that does not have a positive or negative charge.neutronA particle found in the nucleus of an atom. It is almost identical inmass to a proton, but carries no electric charge.nmAn abbreviation for nanometers. A nanometer is equal to 10-9 meters. nucleusThe central part of an atom that contains the protons and neutrons.Plural nuclei.OoctetIn Lewis structures the goal is to make almost all atoms have an octet.This means that they will have access to 8 electrons regularly, even if they do have to share some of them.orbitalsAn energy state in the atomic model which describes where anelectron will likely be.oxidation numberA number assigned to each atom to help keep track of the electronsduring a redox-reaction.oxidation reactionA reaction where a substance loses electrons.oxidation-reduction-reactionA reaction involving the transfer of electrons.oxoacidWhen one or more hydroxide (OH) groups are bonded to a centralatom.Pparent isotopeAn element that undergoes nuclear decay.partial pressureThe pressure exerted by a certain gas in a mixture.particleSmall portion of matter.percent compositionExpresses the mass ratio between different elements in a compound. periodic tableGrouping of the known elements by their number of protons. Thereare many other trends such as size of elements and electronegativitythat are easily expressed in terms of the periodic table.pHMeasures the acidity of a solution. It is the negative log of theconcentration of the hydrogen ions in a substance.photonMassless packet of energy, which behaves like both a wave and aparticle.physical propertyA property that can be measured without changing the chemicalcomposition of a substance.pi bondsA type of covalent bond in which the electron density is concentratedaround the line bonding the atoms.PlanckPlanck contributed to the understanding of the electromagneticspectrum by realizing that the relationship between the change inenergy and frequency is quantized according to the equation ∇ E=hv where h is Planck's constant.pOHMeasures the basicity of a solution. It is the negative log of theconcentration of the hydroxide ions.polar moleculesMolecule with a partial charge.potential energyThe energy an object has because of its composition or position. pressureForce per unit area.principal quantum numberThe number related to the amount of energy an electron has andtherefore describing which shell the electron is in.productsThe compounds that are formed when a reaction goes to completion. proportionAn equality between two ratios.protonParticle found in a nucleus with a positive charge. Number of thesegives atomic number.QquantumSomething which comes in discrete units, for example, money isquantized (divided into units); it comes in quanta (divisions) of onecent.quantum numbersSet of numbers used to completely describe an electron.Rradiant energyEnergy which is transmitted away from its source, for example,energy that is emitted when electrons transition down from one level to another.radiationEnergy in the form of photons.radioactiveSubstance containing an element which decays.ratioThe relative size of two quantities expressed as the quotient of onedivided by the other; the ratio of a to b is written as a:b or a/b. reactantsSubstances initially present in a chemical reaction.reduction reactionA reaction in which a substance gains at least one electron.SsaltsIonic compounds that can be formed by replacing one or more of the hydrogen ions of an acid with another positive ion.shellsWhere the electrons generally are. These shells are composed of 4types of electron subshells: s, p, d and f subshells.sigma bondsA type of covalent bond in which most of the electrons are located inbetween the nuclei.single bondWhen an electron pair is shared by two atoms.SI UnitStands for Systeme International d'Unites, a international systemwhich established a uniform set of measurement units.soluteThe substance (solid, liquid, or gas) dissolved in a solution, forexample, the salt in saltwater.solutionMixture of a solid and a liquid where the solid never settles out, forexample, saltwater.solventLiquid in which something is dissolved, for example, the water insaltwater.specific heatThe amount of heat it takes for a substance to be raised 1°C. spontaneous reactionA reaction that will proceed without any outside energy.state propertyA state property is a quantity that is independent of how the substancewas prepared. Examples of state properties are altitude, pressure,volume, temperature and internal energy.states of matterSolid, liquid, gas and plasma. Plasma is a "soup" of disassociatednuclei and electrons, normally found only in stellar objects. stoichiometryThe study of the relationships between amounts of products andreactants.STPStandard temperature and pressure. This is 0o C and 1 atm.subshellOne part of a level, each of which can hold different numbers ofelectrons.TtermEach compound or element in a chemical equation. thermodynamicsThe study of temperature, pressure, volume, and energy flow inchemical reactions.titrationThe process used to take a solution of unknown concentration with asolution of a known concentration for the purpose of finding out more about the unknown solution.Vvalence electronsThe electrons in the outermost shell of an atom.van der Waals equationAn equation for non-ideal gasses that accounts for intermolecularattraction and the volumes occupied by the gas molecules.velocitySpeed of an object; the change in position over time.volumeMeasures the size of an object using length measurements in threedimensions.WwaveA signal which propagates through space, much like a water wavemoves through water.wavelengthOn a periodic curve, the length between two consecutive troughs (low points) or peaks (high points).weak acidSubstances capable of donating hydrogen but do not completelyionize in solution.weak basesSubstances capable of accepting hydrogen but do not completelyionize in solution.workExpression of the movement of an object against some force.。
有机化学-醇类——英语
Step 2: Loss of H2O gives a carbocation intermediate.
10-26
Reaction with HX - SN1
Step 3: Reaction of the carbocation intermediate (an electrophile) with halide ion (a nucleophile) gives the product.
• The strength of hydrogen bonding in water is approximately 21 kJ (5 kcal)/mol. • Hydrogen bonds are considerably weaker than covalent bonds. • Nonetheless, they can have a significant effect on physical properties.
These alcohols react by a concerted loss of HOH and migration of an alkyl group.
10-29
Reaction with HX
• Step 1: Proton transfer gives an oxonium ion.
• Step 2: Concerted elimination of HOH and migration of a methyl group gives a 3° carbocation.
10-20
Reaction with Metals
Alcohols react with Li, Na, K, and other active metals to liberate hydrogen gas and form metal alkoxides.
structure of molecule
Chapter 10: Chemical Bonding II – Molecular Geometry & Intermolecular Forces 10.1: Molecular GeometryMolecular Structure: - the three-dimensional arrangement of atoms in a molecule.Valence Shell Electron-Pair Repulsion (VSEPR) Model:- the best structure for a molecule is one that minimizes electrons lone pairs repulsion.- most often used to predict molecular structures involving non-metals.Example: For molecules with a total of 4 e− pairs, the bond angles decreases from 109.5° as more lone pairs added. (Repulsion of Lone Pair(s) with bond electrons pushed the angle down.) Effective Electron Pairs: - sometimes refer to as substituents.-the number of lone pairs on the central atom of a molecule and the number of connectionsbetween the central atom with the outer atom(s). Each set of Multiple Bond (like double and triple bonds) count as one connection or one effective electron pair.Summary of Geometrical Shape of Covalent MoleculesCopyrighted by Gabriel Tang B.Ed., B.Sc. Page 123.Page 124. Copyrighted by Gabriel Tang B.Ed., B.Sc.Example 1: From Example 2 of Sections 9.7 & 9.8, determine the geometrical shape of SO32−. What is theCopyrighted by Gabriel Tang B.Ed., B.Sc. Page 125.Page 126. Copyrighted by Gabriel Tang B.Ed., B.Sc.Molecular Geometry of More than One Central Atom : - describe the geometry for each central atom.Example 2: Determine the geometrical shape of ethanol around each central atom. What are the possible10.2: Dipole MomentsDipole Moments (Dipolar): - the direction of the charge distribution of a polar molecule.- the length of the vector indicates the strength of the relative bond polarity, whereas the arrow head indicates the direction of the higher electronegative atom (negatively shifted).Example 1: Draw the molecular structures. Determine the dipole moments (if any) and their overallpolarity of the following molecules.b.Positive Pole (Less Electronegative) Negative Pole (More Electronegative)Copyrighted by Gabriel Tang B.Ed., B.Sc. Page 127.12.2: Intermolecular ForcesIntermolecular Forces : - attraction forces between molecules in a compound- the strengths of the intermolecular forces explain the physical properties of compounds (solubility, boiling and freezing points).a. van der Waals Forces : - Johannes van der Waals studied real gases and molecular interactions.- there are two kinds of van der Waals forces.- they are Dispersion Forces and Dipole-Dipole Interactions .i. Dispersion Forces : - also known as London Dispersion Forces (named after Fritz London who firstproposed how this force works).- on average, the non-polar molecules do not have any permanent dipoles like polar moleculesPage 128. Copyrighted by Gabriel Tang B.Ed., B.Sc.- the “dispersion ” is the temporary dipole that forms within the molecules even in non-polarmolecules due the constant motions of electrons. In one instance, they can move to one side of the molecule making it temporary polar. In another instance, electrons will move and the direction of this temporary dipole will switch.- This constant “sloshing around” of electrons causes non-polar molecules to have these temporary dipoles . These temporary “induced ” dipoles are what cause the attractions between non-polar molecules.- even monoatomic element like Helium has London Forces. (Check out animation at http://www.super-tech.ro/teoretic.html )- in general, the higher the molar mass or the more electrons there are in a molecule , thestronger the London Dispersion Force (attraction between molecules – intermolecular force). This causes an increase in melting and boiling points of the chemical .- N ote: All molecules have electrons. Hence, ALL molecules have London Dispersion Force.Example 1: Explain the boiling points and the melting points of the noble gases.Noble Gases# of e − Molar Mass (g/mol) Melting Point Boiling PointHe 2 4.00 −272°C (1 K) −269°C (4 K) Ne 10 20.18 −249°C (24 K) −246° C (27 K) Ar 18 39.95 −189°C (84 K) −186° C (87 K) Kr 36 83.80 −157° C (116 K) −153°C (120 K) Xe 54 131.29 −112°C (161 K) −108° C (165 K) Rn 86 222.00 −71°C (202 K) −62° C (211 K)δ +δ −δ +δ−“Electrons sloshing ”causes Temporary dipolesAll atoms of noble gases are monoatomic non-polar . The only intermolecular force that governs the melting and boiling points is the London Dispersion Force . As the number of electrons in the noble gases increase , London dispersion force makes the attraction between the atoms greater. This in turn has an effect of increasing the boiling and melting point of the noble gas as one goes down the column.HHδ + δ −HHδ +δ −HHδ +δ −HHδ +δ −Hδ −δ + H Hδ −+Hδ −+H Hδ −+Dispersion Forces Dispersion Forces Dispersion Forcesii.Dipole-Dipole Interaction: - also known as simply Dipole Interaction or Dipole-Dipole Force- intermolecular forces resulted from polar molecules.Example 2: Order the boiling points from the least to greatest for the following compounds with similar molar mass. PH 3 (34.00 g/mol), CH3F (34.04 g/mol), and SiH4 (32.13 g/mol)OClCl 3.23.23.4forOCl2δ +δ +δ−2δ−Since PH3, CH3F and SiH4 have similar molar mass; any differences in boiling points cannot be due to London Dispersion forces. Since dipole-dipole interactions exist in polar molecules, wehave to examine the molecular geometry and structure of each compound.PHHH2.22.22.22.2OofPH3δ +HHH2.234.0SiHHH2.6HCopyrighted by Gabriel Tang B.Ed., B.Sc. Page 129.Page 130. Copyrighted by Gabriel Tang B.Ed., B.Sc.b. Hydrogen Bonds : - are intermolecular bonds that involve hydrogen atom with veryelectronegative atom that also consists of lone pairs .- these include O −H, N −H, and H −Cl and H −F bonds .- the resulting molecule is always polar. Therefore, all hydrogen bonding molecules also have dipole interactions .- hydrogen bond is the STRONGEST of the intermolecular bonds amongst molecular compounds .(Check out the Hydrogen Bond Animation at/biology/Biology1111/animations/hydrogenbonds.html )Example 3: Account for the differences in the boiling points of the compounds listed below.Molecule Molar Mass (g/mol) London Dispersion Forces DipoleInteractionsHydrogen BondsBoiling Point OF 254.0099U−145°C (128 K)Ne20.18 9UU−246°C (27 K) HF 20.01 9 9 9 19°C (292 K) H 2O 18.02 9 9 9 100°C (373 K) NH 3 17.04 9 9 9 −33°C (240 K) CH 416.05 9UU−161°C (112 K)H H N Hδ+ δ+ δ+3δ− Hydrogen BondingExample 4: Given the graph below on the boiling points of hydrogen compounds with different group series, explain the following using the concepts of chemical bonding.a.The hydrogen compounds in the Group (VIA) series have higher boiling points than hydrogencompounds in the other series.b.The first hydrogen compounds in Groups (VA), (VIA) and (VIIA), namely NH3, H2O and HF,have higher boiling points than most other hydrogen compounds in their respective series. Onthe other hand CH4 has a lowest boiling point in its own Group (IVA) series.a. All hydrogen compounds in the Group (VIA) series are very polar and most have hydrogenbonds.The V-shape molecules characterized in Group (VIA) create a greater dipole moment than other series (Group (VA) with its trigonal pyramid shape and Group (VIIA) with itslinear form). On the other hand, all hydrogen compounds in the Group (IVA) series are non-polar and only have London dispersion forces. Since hydrogen bonds are strongerintermolecular forces than London dispersion forces,the hydrogen compounds in the Group (IVA) series have the lowest boiling points than the counterparts in the other series.b. NH3,HF and H2O have stronger hydrogen bonds than most other hydrogen compounds intheir series. The difference between the electronegativities with H is the greatest in row 2(Electronegativities increase from left to right and from bottom to top of the Table). This huge difference in electronegativities in NH3, HF and H2O is what causes their boiling points tobuckle the trend. After NH3, HF and H2O the rest of the hydrogen compounds in the respective series follow the effect of London dispersion forces, the higher the molar mass, the stronger the dispersion forces, and the increase in boiling points is the result.CH4 in the Group (IVA) series do not buckle the trend because the entire series are non-polar.The only intermolecular force at work is the London dispersion force.Hence, CH4 has a lower boiling point than SiH4.Copyrighted by Gabriel Tang B.Ed., B.Sc. Page 131.Page 132. Copyrighted by Gabriel Tang B.Ed., B.Sc.c. Ion-Dipole Force : - when ionic compounds dissolve in water, the cation and anion componentsseparate from one another. These ions are then attracted by the polar water molecules.- ion-dipole force is the STRONGEST of all intermolecular forces.Example : Sodium Chloride (Salt)NaCl (s ) ⎯⎯→⎯OH 2 Na + (aq ) + Cl − (aq )1. Intermolecular Bonds involve in a compound explain its physical properties such as solubility(“like dissolves like ”), boiling and melting points (energy involved in physical phase change).2. van der Waals Forces consist of London Dispersion forces (apply to all molecules) and DipoleInteractions (apply to polar molecules).3. Hydrogen Bond is the STRONGEST of the intermolecular bonds amongst molecular compounds4. Ion-Dipole Force is the strongest of all intermolecular bonds.Summary of Intermolecular ForcesHonour Chemistry Unit 3: Quantum Theory, Periodicity and Chemical Bonding Copyrighted by Gabriel Tang B.Ed., B.Sc. Page 133. Properties of Covalent Crystalline Solids (Metalloid Network Covalent)1. Metalloids : - consists of elements near the “staircase ” of the Table (Examples are carbon in a form ofdiamond and silicon dioxide in a form of quartz crystal).2. Three-Dimensional Network Solids as they form giant molecules by directional covalent bonding (contains no discrete molecular units where an array or network of atoms are held together by conventional covelent bonds, which are directional with dipoles of neighboring atoms .3. Covalent Compounds are Hard and have High Melting Points. This is due to a more organized crystalline structure and covalent bonds are strong intramolecular bonds.4. Covalent Compounds are Relatively Poor Heat and Electric Conductors (or Good Heat or Electric Insulators). Covalent compounds do not have any charge particles like ions. Therefore, they cannot conduct heat and electricity well. An exception is silicon elements . (Silicon has smaller networks than diamonds, allowing some electrons to pass through. Hence, silicon is called a semiconductor .)Example : Alloptropes of CarbonProperties of Molecular Crystalline Solids1. Molecular Compounds tend to have much Lower Boiling and Melting Points than ionic compounds. This is because solid molecular compounds use weak intermolecular forces to form their lattice structures , which does not take much energy to break them. Their boiling points are lower than ionic compounds because there are no ion interactions in liquid state, only intermolecular forces .2. Molecular Compounds are Soft. Again, molecular compounds have a weak lattice structure made of intermolecular bondsthat makes them soft.Carbon as Graphite has weak layered with delocalized bonding network (only some carbon atoms are connected – for each layer is 2sp 2 hybridized which explains its hardness and brittleness). The layers are connected by weak van der Waal forces and hence, graphite can be slippery to the touch. For this reason, we can use it as a lubricant. Carbon as Diamond has strong tetrahedral network (2sp 3) where all four bonding sites of each carbon atoms are connected. Hence, diamond is the hardest material known, and it has an extremely highmelting point (3550°C). Carbon Network as C 60, Buckminsterfullerene , was discovered in 1985. Fullerenes are a family of carbon allotropes, molecules composed entirely of carbon, in the form of a hollow sphere, ellipsoid, tube, or plane.Unit 3: Quantum Theory, Periodicity and Chemical Bonding Honour ChemistryPage 134. Copyrighted by Gabriel Tang B.Ed., B.Sc.3. Some Molecular Compounds and Elements tend to be More Flammable than ionic compound. This is due to the some non-metals like sucrose and sulfur, which combine readily with oxygen in combustion reactions .4. Most Molecular Compounds are Insoluble in Water. Because water is very polar, and it has lots of hydrogen bonds, it can only dissolve molecular compounds that are polar as well “Like Dissolves Like ”. Since most molecular compounds are fairly non-polar , they do not dissolve in polar water well.5. Molecular Compounds do NOT Conduct Electricity in their Solid States due to a lack of delocalized electrons.6. Soluble Molecular Compounds do NOT Conduct Electricity in Water. This is simply due to the fact that molecular compounds do not dissociate into ions or electrolytes like soluble ioniccompounds do.Due to the hydrogen bonds in water, it forms a honeycomb shape and expands in volumewhen it crystallizes into ice. Even though no two snowflakes are alike, all of themhave a basic hexagonal shape as dictated by the bentshape of water molecule and its hydrogen bonds. Dry Ice, CO 2 (s ), is a covalent compoundthat has a crystalline structure. Even a halogen like I 2 (s )has a crystalline structure. Phosphorus, P 4 (s ) can form crystalline structure.。
术语表
索引Aabsorption, infra-red 吸收，红外线acids 酸actinides锕系元素activated complex 活化络合物activated energy 活化能and catalysts 及催化剂addition polymerization 加聚作用（加成聚合作用）adsorption 吸收alcoholic drinks 醇类饮料alcohols 醇类aldehydes 醛类definition 定义alkali 碱and chlorine 及氯alkali metals 碱金属alkaline earth metals 碱土金属alkanes 烷烃combustion 燃烧cracking 裂解alkenes 烯烃asymmetrical 不对称烯烃polymerization 烯烃聚合reactions 反应allotropes 同素异形体alloys 合金aluminium 铝extraction 萃取amines 胺类ammona 氨水molecular shape 分子形状oxidation state 氧化态reaction with haloalkanes 与卤代烷反应ammonium ion铵离子anaerobic respiration 厌氧呼吸antifreeze 防冻剂argon 氩aromatic compounds 芳香族化合物atom 院子models 模型radius 半径atom economy 原子经济性atomic mass,relative 相对原子质量atomic number 原子数atomic orbitals 原子轨道Avogadro constant阿伏加德罗常数Bbalanced symbol equations 平衡符号等式barium钡barium hydroxide 氢氧化钡barium meal 钡餐barium sulfate 硫酸钡bauxite 铝矾土Becquerel,Henri亨利·贝克勒尔Benedict’s test贝内迪克特试验beryllium,electron arrangement铍的电子排列beta-pleated sheet β-折叠片层biodegradability 生物降解性biofuels 生物燃料blast furnace 高炉（鼓风炉）Bohr,Niels尼尔斯·玻尔boiling 沸腾boiling point 沸点alcohols 醇类alkanes 烷烃haloalkanes 卤代烷halogens 卤素hydrides 氢化物hydrocarbons 碳氢化合物metals 金属noble gases 稀有气体Period 3 elements 第三周期元素bomb calorimeter氧弹量热器bond energy 键能bond enthalpies 键焓haloalkanes 卤代烷bonds 键covalent 共价键enthalpy 焓infra-red absorption 红外吸收polarity 极性hydrogen 氢ionic 离子的metallic 金属的boron,electron arrangement 硼的电子排列Bosch,Carl 卡尔·博施Boyle,Robert 罗伯特·玻意耳Boyle’s law玻意耳定律branched chain alkanes 带支链的烷烃Brearley,Harry哈利·布列尔bromine 溴extraction 萃取physical properties 物理性质bromoethane 溴乙烷buckminsterfullerene巴克敏斯特富勒烯Ccaffeine 咖啡因calcium 钙calcium chloride,relative formula mass氯化钙，相对分子质量calcium hydroxide 氢氧化钙calorimeter 热量计carbocation 碳正离子carbon 碳diamond and graphite 钻石和石墨electron arrangement 电子排列electron diagram 电子图in fuels 燃料中isotopes 同位素in organic compounds 有机化合物relative atomic mass 相对院子里in steel 铁中carbon dating碳测定年代carbon dioxide 二氧化碳and ethanol production 及乙醇产生relative molecular mass 相对分子量carbon monoxide 一氧化碳carbon neutrality 碳中性carboxylic acids 羧酸catalysts 催化剂Haber process哈柏法and reversible reactions 及可逆反应catalytic converters 催化转化器catalytic cracking 催化裂解CFCs(chlorofluorocarbons) 氟氯烃Chadwick,James詹姆斯·查德威克chain reactions 链反应chain-branching isomers链分枝异构体charge cloud 电荷云Charles’law 查理定律chemical equilibria 化学平衡chemical feedstock 化学原料chemical reactions 化学反应acid-alkali 酸-碱alcohols 醇类alkenes 烯烃displacement 置换electrophilic addition 亲电加成elimination 消除equilibrium 平衡Group 2 elements 第二主族元素halogens 卤素redox 氧化还原作用reversible 可逆的substitution 取代yields 产率chlorine 氯free radicals 自由基ionic honding 离子键physical properties 物理性质relative atomic mass 相对原子量chlorine tetrafluoride ion 四氟化氯离子co-ordinate bonding 配位键coke 焦煤collision theory 碰撞理论combustion 燃烧alcohol 醇类alkanes 烷烃alkenes 烯烃enthalpy 焓combustion analysis 燃烧分析concentration(of solution) （溶液）浓度conductivity 导电性conservation of energy 能量守恒copper 铜copper oxide 氧化铜empirical formula 最简式（实验式）oxidation state 氧化态reduction 还原copper sulfate 硫酸铜covalent bonds 共价键enthalpy 焓infra-red absorption 红外吸收polarity 极性cracking 裂解crude oil 原油crystals 晶体cyanide ion氰根离子Dd-block,periodic table 周期表d区d-orbitals d轨道Dalton,John 约翰·道尔顿dative covalent bonds 配位共价键decane癸烷dehydration,alcohols 醇类脱水delocalised electrons 离域电子desorption 解吸作用diamond 钻石dichloromethane二氯甲烷dipole moments 偶极距dipole-dipole forces 偶极－偶极力displacement reactions 置换反应displayed formulas 展开式disproportionation歧化反应DNA 脱氧核糖核酸double covalent bonds共价双键in alkenes 烯烃中ductility 延展性dynamic equilibria 动态平衡EE-Z isomerism 顺反异构E-Z标记法electric current 电流electrical conductivity 导电性metals 金属electron cloud 电子云electron density 电子密度electron diagrams 电子图electron pair repulsion theory价层电子排斥理论electronegativity 负电性haloalkanes 卤代烷electrons 电子arrangements 排布delocalized 离域的pairs 电子对in organic reactions 有机反应中的电子对in redox reactions 氧化还原反应中的电子对removal in ionisation 离子化作用中失去电子对shells 电子层spin 电子旋转electrophiles 亲电体electrophilic additions 亲电加成electrostatic forces 静电力within molecules 分子内elimination 消除empirical formulae 最简式（实验式）and combustion analysis 及燃烧分析organic compounds 有机化合物endothermic reactions 吸热反应energy levels 能级energy values(of fuels) （燃料）能量值enthalpy change 焓变of combustion 燃烧measurement 测量reversible reactions 可逆反应see also standard enthalpy change 另见标准焓变enthalpy diagrams 焓图entity 实体epoxyethane环氧乙烷epsom salts 泻利盐equilibria 平衡equilibrium mixtures 平衡混合物equilibrium reactions 平衡翻译industrial 工业的error 错误ethanal乙醛ethane 乙烷molecular formula 分子式ethanoic acid 醋酸（乙酸）ethanol 乙醇infra-red spectrum 红外光谱mass spectrum 质谱oxidation 氧化production 生成ethane 乙烷molecular formula 分子式ethyne 乙烯exothermic reactions 放热反应Ffats,unsaturated 不饱和脂肪f-bolck,periodic 元素周期表table f区feedstock 原料Fehling’s test斐林试剂检测fingerprint region 指纹区first ionisation energy 第一电离能flame calorimeter火焰量热计fluorine 氟electron arrangement 电子排列physical properties 物理性质formulae see displayed formulae 分子式见展开式empirical formulae;molecular 分子最简式formulae;structural formulae 分子结构式fraction 馏分fractional distillation 分馏作用free radicals 自由基fuels 燃料biofuels 生物燃料energy density 能量密度functional group isomers 功能团异构体functional groups 功能团infra-red absorption 红外吸收fusion 融合Ggangue煤矸石gases 燃气Gay-Lussac’s law盖-吕萨克定律geometrical isomers 几何对称异构体germanium, mass spectrum锗的质谱giant structures 巨型结构entity 实体Giotto space probe欧洲空间探测器吉奥托glucose 葡萄糖graphite 石墨greenhouse effect 温室效应Group 2 elements see alkaline earth metals 第二主族元素见碱土金属ionisation energies 电离能Group7 elements see halogens group(periodic table) 第七主族元素见（元素周期表）卤素and atomic radius 及原子半径and electronegativity 及负电性and ionisation energies 及电离能ionisation energy 电离能HHaber process 哈柏法half equations 半反应方程式half-life 半衰期halide ions 卤离子haloalkanes 卤代烷elimination reactions 消除反应formation 生成substitution reactions 取代反应halogens 卤素ions 离子reaction with alkenes 与烯烃反应reactions 反应Hatfield, W.H. 哈特费尔德heat 热conductivity 导热性and temperature 及温度heat loss 热损失heating 加热helium 氦electon arrangement 电子排列in periodic table 元素周期表中Hess, Germain茄曼·盖斯Hess’s law 盖斯定律heterogeneous catalysts 非均相催化剂high resolution mass spectrometry 高分辨率质量光谱Hindenburg airship兴登堡号飞船homogeneous catalysts 均相催化剂homologous series 同系列hydrides 氢化物hydrocarbons 碳氢化合物saturated 饱和烃unsaturated 不饱和烃hydrochloric acid 盐酸hydrogen 氢electron arrangement 电子排列as fuel 用作燃料gas 气体molecular 分子的in periodic table 元素周期表中relative atomic mass 相对原子质量hydrogen bonding 氢键hydrogen sulfide 硫化氢hydroxide ion 氢氧离子as base 用作碱Iibuprofen布洛芬ice 冰ideal gas equation 理想气体方程impurities 杂质incomplete combustion 不完全燃烧industrial processes 工业过程infra-red absorption data 红外吸收数据infra-red spectroscopy 红外光谱intermolecular forces分子间作用力alkanes 烷烃and states of matter 及物质状态iodine 碘physical properties 物理状态ionic bonding 离子键ionic compounds 离子化合物physical properties 物理状态ionic crystals 离子晶体ionic equations 离子方程ionisation,in mass spectrometer 质谱仪电离ionisation energies 电离能Group 2 elements 第二主族元素ions 离子double-charged 双电荷的in ionic bonding 离子键中molecular 分子的shapes 形状iron 铁as catalyst 用作催化剂extraction 萃取iron oxide 氧化铁ironing 熨平衣服isomers 异构体alkanes 烷烃alkenes 烯烃isotopes 同位素Jjoule 焦耳Kkelp 海藻（褐藻）Kelvin scale 开氏温度ketones 酮类Kroto,Harry哈利•克罗托krypton氪Llanthanides镧系元素lattices 栅格Le Chatelier’s principle勒夏特列原理leaving group 离去基团L ewis, Gilbert刘易斯·吉尔伯light 光linear molecules 线性分子liquids 液体lithium,electron arrangement 锂的电子排列lone pairs 孤对（电子）Mmacromolecular crystals 大分子晶体magnesium 镁ionic bonding 离子键oxidation 氧化magnesium nitrate, relative formula mass硝酸镁，相对分子质量magnesium oxide 氧化镁main energy levels 主要能级malleability 可塑性manganese,extraction 镁，萃取mass number 原子质量数mass spectrometry 质谱分析法mass to charge ratio 质荷比Maxwell-Boltzmann麦克斯韦-玻尔兹曼distribution 分布mean bond enthalpies 平均键焓melting 熔化melting points 熔点alcohols 醇类alkaline earth metals 碱土金属halogens 卤素metals 金属Period 3 elements 第三周期元素Mendeleev,Dmitri门捷列夫metal halides 金属卤化物metallic bonding 金属键metallic crystals 金属晶体metals 金属bonding 键extraction 萃取in periodic table 元素周期表中methane 甲烷relative molecular mass 相对分子量methanol 甲醇methoxymethane甲醚milk of magnesia氧化镁乳剂molar mass 摩尔质量mole 摩尔definition 定义of gas 气体定义in solutions 溶液中molecular crystals 分子晶体molecular formulae 分子式organic compounds 有机化合物molecular ions 分子离子molecular mass 分子质量molecules 分子forces between 分之间作用力ionic bonding 离子键shapes 形状monomers 单体Montreal Protocol《蒙特利尔议定书》Nnanotubes 纳米管naptha石脑油neon氖neutralization 中和作用neutrons 中子nitric acid 硝酸nitrogen, electron arrangement 氮的电子排列nitrogen oxides 氧化氮noble gases 稀有气体electronegativity 电负性van der Waals forces 范德华力nomenclature 命名法alcohols醇类aldehydes and ketones 醛类和酮类alkanes 烷烃alkenes 烯烃haloalkanes 卤代烷North Sea oil 挪威北海油nucleons 核子nucleophiles 亲核体nucleophilic substitution 亲核取代nucleus 原子核Ooctahedral molecules 八面体分子octane 辛烷orbitals (electron) （电子）轨道and ionisation energy及电离能orbits, electron 电子轨道ores 矿石organic chemistry 有机化学organic compounds 有机化合物analysis 分析formulae 分子式naming 命名oxidation 氧化alcohols 醇类and halogens 及卤素oxidation states 氧化态in redox equations 氧化还原反应方程中oxidising agents 氧化剂oxygen 氧electron diagram 电子图ionic bonding 离子键relative atomic mass 相对原子质量ozone layer 臭氧层Pp-block,periodic table 元素周期表p区p-orbitals p轨道and alkenes 及烯烃Pauling scale鲍林标度pentane 戊烷percentage yield 百分比产率period 周期Period 3 elements 第三周期元素period 周期and atomic radius 及原子半径and electronegativity 及电负性and ionisation energies 及电离能periodic table 元素周期表Group 2 elements 第二主族元素Group 7 elements 第七主族元素Period 3 elements 第三主族元素periodicity 周期性and ionisation energy 及电离能petrol 石油phase boundaries 相的界限phosphorus 磷electron arrangement 电子排列plastics 塑料plum pudding model(of atom) 原子梅子布丁模型（汤姆孙模型）polar molecules 极性分子alkanes 烷烃haloalkanes 卤代烷pollution 污染polymers 多聚体polythene 聚乙烯positional isomers 位置异构体positive inductive effect 正诱导效应prefixes(nomenclatural)前缀（命名用）pressure 压力and chemical equilibria 及化学平衡and enthalpy 及焓of gas 气体压力and reaction rate 及反应速率primary alcohols 伯醇products 产物propane 丙烷propene 丙烯proteins 蛋白质proton number 质子数protons 质子PVC(polyvinylchloride) 聚氯乙烯Qquantum mechanics 量子力学Rradioactivity 放射性reactants 反应物reaction rates 反应速率reactivity 反应性（反应能力）alkanes 烷烃alkenes 烯烃recycling 循环metals 金属plastics 速率redox equations 氧化还原反应方程redox reactions 氧化还原反应oxidation states 氧化态reducing agents 还原剂metal extraction 金属萃取reduction 还原and halide ions及卤离子halogens 卤素metal oxides 金属氧化物relative atomic mass 相对原子质量and isotopes及同位素relative formula mass 相对分子质量relative molecular mass 相对分子质量gases 气体repeating units 重复单元reversible reactions 可逆反应and catalysts 及催化剂ring alkanes 环烷烃roasting 烧烤roots(nomenclatural) 词根（命名用）Rutherford,Ernest欧内斯特·卢瑟福ss-block,periodic table 元素周期表s区s-orbitals s轨道saturated hydrocarbons 饱和烃Schrodinger,Erwin埃尔文·薛定谔Schrodinger equation 薛定谔方程secondary alcohols仲醇shells,electron 电子层SI units SI国际标准单位silicon 硅silver ions银离子single covalent bonds共价单健slaked lime 熟石灰smog 烟雾sodium 钠electron arrangement 电子排列electron diagram 电子图ionic bonding 离子键ionisation energy 电离能molar mass 摩尔质量sodium bromide 溴化钠sodium chlorate 氯酸钠sodium chloride 氯化钠sodium iodide 碘化钠sodium sulfate 硫酸钠solids 固体heating 加热solubility 溶解性alkanes 烷烃alkaline earth metal 碱土金属compounds 化合物haloalkanes 卤代烷solute 溶质solutions 溶液concentration 浓度enthalpy changes 焓变redox reactions 氧化还原反应solvent 溶剂specific heat capacity 比热容spectator ions 旁观离子spin 自旋stainless steel 不锈钢standard molar enthalpy change 标准摩尔焓变of combustion 燃烧的of formation 生产的states of matter 物质状态and enthalpy change 及焓变steel 钢stereoisomers 立体异构体stoichiometry 化学计量学strong nuclear force 强核力strontium锶strontium hydroxide氢氧化锶structural formulae 结构式structural isomers 结构异构体structures 结构sub-atomic particles 亚原子结构sub-levels 次级substitution reactions 取代反应free-radical 自由基nucleophilic 亲核的suffixes(nomenclatural) 后缀（命名用）sulfate ion 硫酸根离子sulfur 硫sulfur dioxide 二氧化硫sulfuric acid 硫酸sun spots 太阳黑子TTeflon特氟纶（聚四氟乙烯）temperature 温度equilibrium reactions 平衡反应of gas 气体的平衡反应and heat 及热量and reaction rate 及反应速率tertiary alcohols 叔醇tertiary alctetrachloromethanetetrahedral molecules 四面体分子thermal cracking 热裂解thermit reaction西尔米特反应（铝热反应）thermochemical cycle 热化学循环thermochemistry 热化学Thiobacillus ferrooxidans氧化亚铁硫杆菌Thomson J.J. 汤姆森titanium,extraction钛的萃取titrations 滴定Tollens’test 银镜反应（托伦试剂反应）transition elements 过渡元素transition state 过渡态trigonal bipyramid三角双锥trigonal planar molecules 三角平面分子triple covalent bonds共价三键tungsten 钨extraction 萃取Uunbranched chains 未分支链uncertainty 不确定性and pressure 及压力unsaturated fats 不饱和脂肪unsaturated hydrocarbons 不饱和烃Vvan der Waals forces 范德华力vanadium 钒vaporization 蒸发VikingMartian landervolume(of gas) （气体）容量Wwater 水and chlorine 及氯气evaporation 蒸发and Group 2 elements 及第二主族元素ice 冰molecular mass 分子质量vapour 蒸汽water sampling 水取样Wohler,Friedrich弗里德里希·维勒Yyields 产率Zzeolites沸石。
分子间作用力 Intermolecular Forces
配位数：6
代表元素：Po
（例题见7-2ppt35-41p）
Body Centred Cubic Lattices
每晶格含有原子数：(8 x 1/8) + 1=2
空间占用率：68%
配位数：8
代表元素：U
（例题见7-2ppt44-47p）
Face Centred Cubic Lattices
Crystal lattice晶格：一组相同的晶胞
Cubic Unit Cell立方相晶胞：长宽高三边相等且夹角均为90度的晶胞
晶格类型
Simple Cubic Lattices
每晶格含有原子数：8 x 1/8 = 1
晶格体积：(2r)3= 8r3
原子占用空间：8 (1/8) (4/3pr3)=4/3pr3
指液体流动的阻力，由三个因素决定
1.分子间作用力（如碳水化合物水溶液hydrocarbons vs. water）
2.液体中有机分子的碳链长度
3.液体的温度（如发动机润滑油粘性随温度变化）
Vapour Pressure
液体与其蒸汽在封闭容器中达到动态平衡的压力。
固体与分子间作用力
固体液体中粒子状态的区别
Surface Tension
由液体的分子间作用力产生（液面分子受到的净作用力指向液面下方）
液体的表面分子有一种吸引的内力，形成液面，液面的韧性称为表面张力
定义为液面对表面积增加所产生的阻力，单位为N/m或J/m2
表面张力与粒子间作用力的关系
Surfacetension, J/m2
CH3(CH2)2CH3(l)
very hard
更坚硬
tools
工具
Chromoly Steel铬钼钢：Fe, C, Si, Mn, Mo, Cr
化学键原理概述
abundant. • In the vapor phase over liquid carboxylic acids, doublH•••NH3 HOH•••OH2 H2NH•••NH3 N-H•••O
Typical Bond Energy 161 kJ/mol (the bifluoride ion) 29 kJ/mol 21 kJ/mol 13 kJ/mol
8 kJ/mol
Hydrogen Bonding (continued)
Ionic Bonds
Crystal LiF NaCl KBr CsI
Melting Point 1118 K 1074 K 1007 K 894 K
Crystal
NaF
Na2O MgF2 MgO
Melting Point 1266 K 1405 K 1536 K 3125 K
Ionic Bonds
Ionic Bonds – These are easily understood as arising from the Coulomb attraction between ions with opposite charges
Covalent Bonds – These are more difficult to understand, and really require quantum mechanics
Dispersion Forces
Even in highly symmetric molecules (CH4, for example) or atoms (He, Ne, Ar,…), the charge distribution is not always symmetric. There is always a probability that the electrons at any instant will be asymmetric, as illustrated here:
药物化学原理课件-Lecture-03
1Summary of Last lecture •Lead Modification•Search for the active part (Pharmacophore, 药效团)•Structure-activity relationship (SARs)•Functional group modification •Drug-like molecules •Structure modifications•Bioisoterism (生物电子等排原理)•To increase potency and therapeutic index •To increase oral bioavailability•Pharmacokinetics, Metabolism andPharmacodynamics (药动，药代和药效)2Summary of Last Lecture (cont’d)•Pharmaceutical Phase•Selection of administration route (给药途径)to optimizeabsorption and distribution and or most appropriate formulation for maximal benefits •Pharmacokinetic Phase•Fate of the drug in the body (ADME), the ration ofadministrated dose to the concentration of the drug at the site of action as the function of time •Pharmacodynamic Phase•Quality of the drug-target response (maximal activity and selectivity, minimal toxicity), and nature and intensity of the biological response)3Scheme of in vivo Events CirculationBoundUnboundDistributionIntravenous Fat StorageLiver Metabolism:Metabolic activation Metabolic degradationKidney Intestine LungUrine Faeces Expired airAdministration of a drug AbsorptionMembrane BarrierMembrane BarrierParenteral RouteEnteralRouteB i o l o g i c a l l y a v a l i a b l eInteraction w/the receptor site of the target organBiological Response4Pharmacodynamic Phase•The phase of great interest to the medicinal chemist asit deals directly with the nature and the quality of the interaction of the drug with its biological target •The challenge is to maximize the potency and to minimize undesired effects of the molecule•Try to design drugs with the optimal size, shape,hydrophilic-lipophilic ratio, and disposition of functional groups•The closer the fit obtained between the receptor site and the molecules, the more selective will be the drug in eliciting only the expected biological response5Med. Chem. LectureOctober 14, 2009Lei Fu （傅磊）, Ph.D.leifu@ 上海交通大学药学院药物化学课题组6Outline•Term Paper Assignment •Term Paper Preparation •Receptor (受体)•Drug-Receptor Interactions7Course Content (cont’d)•Lectures (September 16, 23, 30)•No lecture on October 7th •Lectures (October 14, 21, 28)•Term paper assignment (by September 30)•Term paper preparation (about one month)•Term paper presentation (November 4, 11)•Term paper due (w/ppt, November 2nd )8Outline•Term Paper Assignment •Term Paper Preparation •Receptor (受体)•Drug-Receptor Interactions9Scheme of in vivo EventsCirculationBoundUnboundDistributionIntravenous Fat StorageLiver Metabolism:Metabolic activation Metabolic degradationKidney Intestine LungUrine Faeces Expired airAdministration of a drug AbsorptionMembrane BarrierMembrane BarrierParenteral RouteEnteralRouteB i o l o g i c a l l y a v a l i a b l eInteraction w/the receptor site of the target organBiological Response10Receptor (受体)Definition• A receptor is the site of drug action, which isultimately responsible for the pharmaceutical effect•Molecular structure in or on a cell thatspecifically recognizes and binds to acompound and acts as a physiological signal transducer, or mediator of, an effect (IUPAC)11Receptor (cont’d)•Mostly membrane-boundproteins that selectively bind small molecules, referred to as ligands, that cause somephysiological response •Generally integral proteins that are embedded in thephospholipid bilayer of cell membranesNeurotransmitter receptorsLigands12Receptor (cont’d)•Once dissociated fromthe membranes, they generally lose their integrity•Typically characterizedin terms of their function rather than by their structural propertiesThe Nicotine Receptor13Outline •Term Paper Assignment •Term Paper Preparation •Receptor (受体)•Drug-Receptor Interactions14Drug-Receptor InteractionsThe interaction is an equilibrium rather than anone-to-one interaction•Drug (200Mw, 10mg):(6.02x1023)(10x10-3)/200=3x1019•Each cell: 1010molecules•Human organism: 3x1013cells or 3x1023molecules •Cell molecules/drug molecules = 10415Drug-Receptor InteractionsThe measurement of the drug-receptor interactions•The dissociation constant K d•K d = [drug][receptor] / [drug-receptor complex]•The smaller the K d , the more stable is thecomplex, and the greater is the affinity of the drug for the receptor16Types of Interactions1.Covalent Bonds2.Ionic (or electrostatic) Interactions3.Ion-Dipole and Dipole-Dipole Interactions4.Hydrogen Bonds5.Charge-Transfer Complexes6.Hydrophobic Interactions17Covalent Bonds •The strongest bond, worth -40 to -110 kcal/molin stability•Seldom formed by a drug-receptor interaction,except with enzymes and DNA18Ionic (or electrostatic) Interactions•At physiological pH=7.4, the amino side chains of arginine, lysine, histidine areprotonated, and provide a cationic environment; acidic groups are deprotonated to give anionic groups•The ionic interaction can be effective at distances farther than those required for other types of interactionsExample of an electrostatic interaction ΔG o = -5 to -10 kcal/molPivagabine is an antidepressant drug Wavy line represents the receptor surface19Ion-Dipole & Dipole-Dipole•As a result of electro-negativity difference between C and X (O, N, S, F, Cl etc.)•Asymmetric distribution of electrons produces electronic dipoles •A dipole-dipoleinteraction is weaker than an ion-dipole interactionExample of Ion-Dipole & Dipole-Dipole InteractionsΔG o = -1 to -7 kcal/molWavy line represents the receptor surface20Hydrogen Bonds•A type of dipole-dipoleinteraction formed between H and an electronegative atom and other electro-negative atom with a pair ofnonbonding electrons: N, O, F •H is the only atom carries a positive charge atphysiological pH whileremaining covalently bonded in a moleculeExample of H-bond interactions ΔG o = -3 to -5 kcal/molSalicylic acid (水杨酸)is used in wart removal remediesWavy line represents the receptor surface21Charge-Transfer Interactions•Between e -donor and e -acceptor•The donor will transfersome of its charge to the acceptor, forming a charge-transfer complex•Donor: aromatic moieties,π-electrons, O, N, S•Acceptor: e --deficient π-orbitalsExample of a charge-transfer interaction ΔG o = -1 to -7 kcal/molChlorothalonil (百菌清)is a fungicide Wavy line represents the receptor surface22Hydrophobic Interactions•In the presence of a nonpolar molecule or region of a molecule, the surrounding water molecules orient themselves and are in a higher energy state•When meet, these watermolecules become disordered in an attempt to associate with each other •ΔG(↓) = ΔH –T ΔS(↑)Example of hydrophobic interaction ΔG o = -0.7 kcal/molButamben is a topical anesthetic drug Wavy line represents the receptor surface23Example of Multiple Interactions Dibucaine (二丁卡因，局部麻醉剂)24Example of Multiple InteractionsDibucaine (二丁卡因，局部麻醉剂)25Example of Multiple Interactions Dibucaine (二丁卡因，局部麻醉剂)26Conclusions•Cooperativity by several types of interactions is critical.The effect of this cooperativity is that several rather weak interactions may combine to produce a strong interaction•ΔG = ΔH -T ΔS•To a first approximation, enthalpy (ΔH) term will beadditive, then, translational entropy (ΔS) is lost•Charge groups bind more strongly than polar groups,which bind more tightly than nonpolar groups27QuizIndicate what drug-receptor interactions are involved at each arrow shown1.Ion-dipole interaction2.Dipole-dipole interaction3.Hydrophobic effect4.Hydrogen bonding5.Electrostatic interaction and/or hydrogen bondingabdec28Quiz (answer key)Indicate what drug-receptor interactions are involved at each arrow shown1.Ion-dipole interaction2.Dipole-dipole interaction3.Hydrophobic effect4.Hydrogen bonding5.Electrostatic interaction and/or hydrogen bondingabdecAnswer key: a-5, b-4, c-3, d-2, and e-1。
Factors that Affect Solubility
A decrease in pressure means not as much solubility
Solvation is when no particular solvent is mentioned, the solute particles are said to be solvated.
Hydration is when water is the solvent, and the solute particles are said to be hydrated.
Let’s See it!
London (dispersion) Forces
Weakest intermolecular force between non polar molecules It is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles
Non-polar Molecules
A non-polar molecule is one that the e- are distributed more symmetrically and thus does not have an abundance of charges at the opposite sides. The charges all cancel out each other.
Exothermic: H3 > (H1 + H2)
Endothermic: H3 < (H1 + H2)
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• The bonds are stronger in solids(more closely packed together) than in liquids(molecules are loose)
Check it Out!
• sumanasinc/webcontent/animations/content/propertiesofwat er/water.html
ComparБайду номын сангаасson
Similarities
• Both interactions are between a positively charged end of a molecule with a negatively charged end of a molecule
Ion-Dipole Forces
• between an ion and a polar molecule
• cations are attracted to the partially negative ends of a neutral polar molecule, while anions are attracted to the partially positive ends of a neutral polar molecule
polar molecule.
The cation, the Na, attracts the oxygen molecules. The positively charged cation is attracted to the negatively charged oxygen polar molecule.
• the most commonly found in solution and is very important for an ionic compound in a polar liquid.
• becomes stronger as the charge on the ion changes or the magnitude of the polarity of the polar molecule increases
strength of the bonds liquids - The weak intermolecular bonds in liquids and solids • Categorized in three groups: dipole-dipole, dipole-
induced dipole, induced dipole-induced dipole
forces.shtml • yteach.co.za/index.php/resources/intermolecular_force_matter_dipol_polar_no
n_polar_dispersion_hydrogen_bonding_t_page_11.html
Ion-Dipole Forces
The cation and anion are attracted to the polar molecules. The anion is attracted to the positive end of the polar molecule, while the cation is attracted to the negative end of the
• Ion-Dipole has a stronger bond than a DipoleDipole bond
Bibliography
• /genchem/topicreview/bp/intermol/intermol.html#for ce
• /gchelp/liquids/dipdip.html • abeliaschemistry.spot/p/dipole-dipole-forces.html • sumanasinc/webcontent/animations/content/propertiesofwater/water.html • /chem/senese/101/liquids/faq/h-bonding-vs-london-
attracted to the partially negative oxygen. This is also considered a hydrogen bond, because the force of attraction between the
hydrogen of one molecule to an electronegative element, which is oxygen.
Dipole-Dipole and Ion-Dipole Interactions
•By: Katlyn, Christina, Jonathan, Jeet
Intermolecular Forces
• Attraction between two molecules • Van der Waals wanted to test the behavior and the
Dipole-Dipole Forces
• When polar molecules come in contact with each other
• partially positive end of a molecule is attracted to a partially negative end and vice-versa.
The partially positive hydrogen is attracted to the partially negative chlorine.
The water molecule is attracted to the other water molecules through dipole-dipole forces. The partially positive hydrogen is
• Hydrogen bonding is a type of dipole-dipole bonding.
Dipole-Dipole Forces
The HCl, or the hydrochloric acid, is attracted to one
another through dipole-dipole forces.
Check it Out!
• yteach.co.za/index.php/resources/intermolecular_force_matt er_dipol_polar_non_polar_dispersion_hydrogen_bonding_t_p age_11.html
• /chem/senese/101/liquids/faq/hbonding-vs-london-forces.shtml
Differences
• Dipole-Dipole interactions are between two polar molecules, while Ion-Dipole interactions are between an ionic compound and a polar compound
Dipole-Dipole Forces
• Not as strong as an ionic bond but is usually stronger than London forces
• Great effect only when the polar molecules are close together