3 Bonding Flashcards Preview

MCAT Organic Chemistry Review > 3 Bonding > Flashcards

Flashcards in 3 Bonding Deck (21)
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1

quantum numbers

size, shape, number, orientation or atomic orbitals in an element

2

principal quantum number (n)

energy level of given electron shell

measure of size

energy increases as "n" increases

3

azimuthal quantum number (l)

electron subshell

0 to n-1

0 = s
1 = p
2 = d
3 = f

energy increases as "l" increases

4

magnetic quantum number (ml)

orbitals (shape)

-"l" to "l"

5

spin quantum number (ms)

each orbital can hold 2 electrons

+/- (1/2)

6

molecular orbitals

when 2 atomic orbitals combine
add/subtract wave functions

7

bonding molecular orbital

if signs of the wave functions are the same

lower-energy (more stable)

8

antibonding molecular orbital

if signs of wave functions are different

higher-energy (less stable)

9

sigma bond

head-to-head/tail-to-tail overlap

allow free rotation about axis

all single bonds

10

pi bond

when 2 p-orbitals line up in parallel, electron clouds overlap
bonding MO forms

hinder rotation, lock atoms in place

cannot exist independently of a sigma bond

11

1 pi bond on existing sigma bond

double bond

12

2 pi bonds on existing sigma bond

triple bond

13

individual pi bonds are _______ (stronger/weaker) than individual sigma bonds

weaker

14

hybrid orbitals

mixing different kinds of orbitals; hybridization

15

sp3 hybrid orbitals

3 p-orbitals + 1 s-orbital
75% p character + 25% s character

tetrahedral geometry

16

sp2 hybrid orbitals

1 s-orbital + 2 p-orbitals
33% s character + 67% p character

trigonal planar geometry (120º apart)

17

What is the function of the unhybridized 3rd p-orbital in sp2 hybridization?

participates in pi bond (alkenes)

18

sp hybrid orbitals

1 s-orbital + 1 p-orbital
50% s character + 50% p character

linear geometry (180º apart)

19

What is the function of the 2 unhybridized p-orbitals in sp hybridization?

2 double bonds --> triple bond (alkynes)

20

conjugation

alternating single and multiple bonds

aligns a number of unhybridized p-orbitals down the backbone of a molecule

pi electron destabilization
--> adds stability
--> electron density distributed throughout structure

21

"true hybrid" of resonance structures

no equilibrium

more stable resonance forms contribute more to the "true hybrid" form