Structure and Bonding

Question 1

Valence Bond theory

Answer 1

half filled atomic orbital on two atoms overlap to create a bond containing paired electrons.

Question 2

Hybridization

Answer 2

Atomic orbitals combined in 4 diff combinations to form hybrid orbitals.
At intermediate energy from lower and higher orbitals.

Question 3

Sigma bond

Answer 3

symmetric to rotation around the bond

Question 4

Pi bond

Answer 4

not symmetric to rotation around the bond

Question 5

Ethene bonding

Answer 5

sp2 orbital overlaps to give sigma bond
sp2 hybridization gives pi bond

Question 6

Valence bond model + -

Answer 6

Helpful in explanation about molecular shape. But localised models on one bond.
Can’t explain paramagnetism of O2.

Question 7

Molecular orbital theory

Answer 7

orbitals combine -constructively for bonding MO. High probability of e found between atoms, contributes to bonding.
-destructively for anti bonding MO. 0 probability of e found between atoms, negates bonding. described with *

Question 8

MO rules

Answer 8

Always same number of MOs as atomic orbitals
Only orbitals of same symmetry will combine.
Atomic orbitals need to be close in energy to overlap.
Electrons fill lower energy orbital first.

Question 9

Bond order formula

Answer 9

number of bonding electrons - number of anti bonding electrons

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