7th - mo bonding on 2nd period elements

Question 1

2p orbitals are

Answer 1

directional
one along each cartesian axis
px py pz

Question 2

when looking at mo we look at

Answer 2

valence electrons only

ignore core electrons
aka: lower n value

Question 3

what atomic orbitals have the most efficient overlap

Answer 3

those with the same or similar energies

2s and 2s

Question 4

why dont we consider core e-

Answer 4

too stable
too little energy for significant overlap

Question 5

what does the cartesian axis, z do

Answer 5

joins 2 atoms together

Question 6

what is a pi bond

Answer 6

when the phases of the orbital are switched/reversed when it is rotated 180

pi: 180 in oven changes it

Question 7

what is a sigma bond

Answer 7

when the phases remain the same after being rotated 180

Question 8

if a mo is formed from 2 ao in the same phase the mo will be aaaaa

Answer 8

sigma mo
all one phase

Question 9

if a mo is formed from 2 ao (s) in opposite phases the mo will be aaaaa

Answer 9

sigma star s orbital
antibonding orbital
node in between the 2 phases in the mo
higher in energy

Question 10

when 2 ao (p) with 2 diff phases bond they form a

Answer 10

the phases that are the same constructively interfere
form a burger type shape with the same phase in the middle and the 2 other phases outside.
no nodes (in phase phases interefered consteuctively)

Question 11

when will u see a node in mo

Answer 11

when 2 opposite phases are present and next to eachother.

Question 12

s orbital is a

Answer 12

sphere shape

Question 13

p orbital is a

Answer 13

dumbbell shape

Question 14

pz points

Answer 14

towards the other atom
its the axis that joins atoms.
line between 2 nucs
thats why pz is sigma, 180 rotation does nothing to its phases.
horizontal chicken leg = pz
Pepez chicken = sigma

Question 15

px and py point

Answer 15

orthoganal
vertical chicken leg
rotation it 180 by the z axis (horizontal axis, will change its phase as it will flip)
pi bond

Question 16

same phases

Answer 16

interact
sigma or pi
bonding mo

Question 17

opposite phases

Answer 17

node in the middle
sigma star or pi star
antibonding mo

Question 18

if a mo has both can combine to form bonding and antibonding
2s (sphere) and 2pz or y
there issss

Answer 18

no overall bonding
just pretend they cancel out

Question 19

what bond has the largest variation in energy in a mo diagram

Answer 19

sigma and sigma star
the p version

Question 20

why do the pi star and pi not have much of an energy gap between them

Answer 20

bc the pz orbitals face eachother / point towards eachother

Question 21

from N to the left side

Answer 21

sigma is higher than pi
1
2
1
2

s and p can mix, sigma goes above pi
connect the sigma to the 2s below

Question 22

from O to the right

Answer 22

s and p are too diff in energy + cant mix, sigma goes under pi

Question 23

rule for knowing if s and p mix

Answer 23

add e- for both atoms
/2
8 or bigger = s and p dont mix
sigma below pi

smaller than 8 = s and p mix
sigma above pi

Question 24

how can molecular orbitals be formed

Answer 24

overlap of atomic orbitals

Question 25

what does MO help us understand

Answer 25

helps us understand molecular properties better