有机化学英文

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h igh er lower
1-5
Electron Configuration of Atoms
Shells are divided into subshells called orbitals, which are designated by the letters s, p, d, f,........
• only two electrons can occupy an orbital and their spins must be paired
Hund’s Rule:
• when orbitals of equal energy are available but there are not enough electrons to fill all of them, one electron is added to each orbital before a second electron is added to any one of them
1-3
Schematic View of an Atom
• a small dense nucleus, diameter 10-14 - 10-15 m, which contains positively charged protons and most of the mass of the atom
ቤተ መጻሕፍቲ ባይዱ1-9
Lewis Dot Structures
Gilbert N. Lewis Valence shell:
• the outermost occupied electron shell of an atom
Valence electrons:
• electrons in the valence shell of an atom; these electrons are used to form chemical bonds and in chemical reactions
Table 1.4 Lewis Dot Structures for Elements 1-18
1A 2A 3A 4A 5A 6A 7A 8A
H.
He :
:: :: ::
.
..
.
.
Li . Be : B : C : .N : :O. : :F : :N e :
.
..
.
.
N a. M g : A l : Si : .P : :S. : :Cl : :A r :
1-7
Electron Configuration of Atoms
The pairing of electron spins
1-8
Electron Configuration of Atoms
Table 1.3 The Ground-State Electron Configuration of Elements 1-18
1-6
Electron Configuration of Atoms
Aufbau Principle:
• orbitals fill in order of increasing energy from lowest energy to highest energy
Pauli Exclusion Principle:
Lewis dot structure:
• the symbol of an element represents the nucleus and all inner shell electrons
• dots represent valence electrons
1-10
Lewis Dot Structures
• about 1000 new ones are identified each day!
C is a small atom
• it forms single, double, and triple bonds • it is intermediate in electronegativity (2.5) • it forms strong bonds with C, H, O, N, and some metals
• an extranuclear space, diameter 10-10 m, which contains negatively charged electrons
1-4
Electron Configuration of Atoms
Electrons are confined to regions of space called principle energy levels (shells)
Organic Chemistry
William H. Brown Christopher S. Foote Brent L. Iverson
1-1
Covalent Bonding & Shapes of Molecules
Chapter 1
1-2
Organic Chemistry
The study of the compounds of carbon Over 10 million compounds have been identified
• each shell can hold 2n2 electrons (n = 1,2,3,4......)
N u mb er of Relative En ergies Electrons S hell of Electrons
S hell Can Hold in Thes e Shells
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• s (one per shell) • p (set of three per shell 2 and higher) • d (set of five per shell 3 and higher) .....
S hell O rb itals Contain ed in Th at S hell 3 3s , 3px, 3py, 3pz, p lu s five 3d orbitals 2 2s , 2px, 2py, 2pz 1 1s