Week 16

Question 1

Gas phase electron transfer

Answer 1

Favourable gas phases are those where the the element that is taking the electron has a higher electronegativity = lower valence orbital energy

Question 2

Born-Oppenheimer

Answer 2

States that electrons are small and can move quickly whilst atomic nuclei are larger and heavier so don’t move as fast

Question 3

Coulomb interactions

Answer 3

Coulomb’s law states opposites attract and like charges repel, energy is given out if two opposite charges move towards each other. Work is needed to pull two opposite charges apart. Interactions get weaker as distance increases

Question 4

Quantum confinement

Answer 4

The more restricted a particle is to stay in a particular volume of space, the higher it’s energy.
The more a particle is allowed to delocalise, the lower it’s energy becomes

Question 5

Potential well

Answer 5

A potential well is the region surrounding a local minimum of potential energy. Energy captured in it cannot convert to another type of energy because it’s captured in the local minimum of a potential well.

Question 6

Valence bond theory

Answer 6

When two orbitals on different atoms overlap, a new bigger orbital forms which allows two electrons to delocalise across the two atoms, lowering them both in energy.

Question 7

Bonding

Answer 7

In phase combination produced an orbital which is lower in energy than the original atomic orbitals

Question 8

Anti-bonding

Answer 8

Out of phase - produced an orbital which is higher in energy than the original orbitals

Question 9

Aufbau principle

Answer 9

Fill the orbitals from the lowest energy up

Question 10

Hunds rule of maximum multiplicity

Answer 10

for orbitals of the same energy, electrons first fill up with all spins parallel, then anti parallel pairings

Question 11

Bond order

Answer 11

Bonding orbital electrons - anti bonding orbital electrons / 1/2

Question 12

Valence on periodic tables

Answer 12

First column is +1
Second Column is + 2
Penultimate colomn is -1
Last colomn is no charge

Question 13

Orbital stability based off of MO

Answer 13

E.g. H2+ has one electron in a bonding orbital and an empty anti bonding so will have a bond order of 0.5 for a weak but stable bond

H2- has two electrons in bonding and one electron in anti bonding and also has a bond order of 0.5 giving the same result

H2 2- is not stable because it has two electrons in a bonding orbital and 2 in the anti bonding so has a bond order of zero

Question 14

HOMO

Answer 14

Highest occupier molecular orbital
Bottom of the MO

Question 15

LUMO

Answer 15

lowest unoccupied molecular orbital

Question 16

SOMO

Answer 16

single occupied molecular orbitals