Bonding, MO Theory, Hybridization, Bond Angles/Geo

Question 1

Heisenberg Uncertainty Principle

Answer 1

• the more precisely we know an e- position, the less precisely we know where it is going and vice versa
• “uncertainty in an electron’s position is inversely proportional to the uncertainty in a measurement of its momentum”

Question 2

S, P, and Hybrid Orbitals

Answer 2

S - spherical; density is held more proximal to nucleus than in p-orbs

P - knob shaped; possess two lobes with opposite phases (bi-phasic); have a node (were electron density cannot be found aka is 0) between the two phases

Hybrid - cross between two or more pure AO; have two lobes of differing size, each with a separate phase; atoms can adopt an sp3, sp2, or sp hybridization state

Question 3

M.O.

Answer 3

• regions of electron density that surround a molecule formed by the overlapping of two atomic orbitals (sigma or pi bonds)

ex - in covalent bonding, # of orbs is conserved so when 2 sp3 orbs overlap, two MO are created - 1 bonding and 1 anti-bonding

Question 4

MO vs AO

Answer 4

In a MO, electron density surrounds the molecule; they have distinct sizes, energies and shapes
In an AO, electron density surrounds the nucleus

Question 5

Constructive vs deconstructive interference

Answer 5

constructive = in-phase and results in the formation of a bonding MO

deconstructive = out of phase and results in formation of anti-bonding MO

Question 6

Sigma vs Pi bond

Answer 6

sigma - a type of MO formed by head on overlap of two hybrid orbitals, two s orbitals, or a hybrid orbital with an s orbital; the overlap occurs along internuclear axis (between the nuclei of the bonding atoms)

pi - MO formed by side-to-side overlap of 2 p orbitals; overlap occurs above and below the internuclear axis

sigma bonds are lower in energy than pi bonds; stronger orbital overlap in sigma bonds than pi because s and hybrid orbitals hold electron density closer to the nucleus

Question 7

covalent bond formation results in the overlap of 2 atomic orbitals (valence electrons) and for every bonding interaction….

Answer 7

there is a complimentary anti-bonding interaction

Question 8

As atoms move closer to one another, their orbitals begin to overlap which results in a ____ of energy until a certain point where the _____ repel one another

Answer 8

in a decrease in energy until the positively charged nuclei repel each other

Question 9

Energy minimum (maximum stability) of orbitals overlapping is

Answer 9

achieved when the attraction of the electrons to the nucleus

Question 10

Atoms that will hybridize

Answer 10

C, N, O, S, P, Al, B, and halogens (F, Cl, Br, I)

Question 11

Energy level of hybrid orbitals

Answer 11

higher in energy than s orbitals but lower in energy than p-orbitals

Question 12

Sp3 (orbs, electron domains, molecular shape, molecular geo, orbital character)

Answer 12

• 4 sp3 orbitals, no p orbitals
• 4 e domains
• tetrahedral (C) - 109.5
• bent (O) - 104.5
• trigonal pyrimidal (N) - 107.3
• 75% p, 25% s character

Question 13

Sp2 (orbs, electron domains, molecular shape, molecular geo, orbital character)

Answer 13

• 3 sp2 orbitals, 1 p orbital
• 3 e domains
• trigonal planar - 129
• 66% p, 33% s character

Question 14

Sp (orbs, electron domains, molecular shape, molecular geo, orbital character)

Answer 14

• 2 sp orbitals, 2 p orbitals
• 2 e domains
• linear - 180
• 50% p, 50% s character

Question 15

Carbocations engaging in a pi-bond are sp hybridized and are also known as

Answer 15

vinyl carbocations

Question 16

If a negatively charged carbon is adjacent to another sp2 atom, it will ___ hybridize to participate in ____

Answer 16

sp2 hybridize to participate in resonance

Question 17

Radicals - the unpaired electron resides in the ____ with each lobe possessing half the density, making it ___ __

Answer 17

unpaired electron resides in the p-orbital and it is highly reactive

Question 18

key to determining hybridization sate is looking at the number of electron domains or identifying the number ____ possessed by an atom

Answer 18

p orbitals

Question 19

what is an electron domain

Answer 19

the number of lone pairs plus the number of single bonds (sigma) an atom engages in

Question 20

Electron domains and hybridization state

Answer 20

sp3 atoms = an atom possessing 4 sp3 orbitals and no p orbitals/ 4 electron domains (no pi-bond interactions)

sp2 atoms = atom possessing 3 sp2 orbitals and 1 p orbital/ 3 electron domains (one pi bond interaction)

sp atoms = atom possessing 2 sp orbitals and 2 p orbitals/ 2 electron domains (two pi bond interactions)

Question 21

Visually determining hybridization state

Answer 21

sp3 atom = atom visually only makes single bonds/doesn’t participate in pi-bond interactions

sp2 atom = atom visually double bonded/participates in 1 pi bond interaction

sp atom = atom visually triple bonded or visually doubly bonded to two distinct atoms/ participates in 2 pi bond interactions

Question 22

carbocats adjacent/next to a double bond are

Answer 22

sp hybridized

Question 23

two distinct double bond interactions

Answer 23

sp hyrbidized

Question 24

radical and carbocats are normally

Answer 24

sp2 hybridized

Question 25

BH3 and AlCl3 are

Answer 25

sp2 hybridized