Hybridization

Question 1

What are the 3 main postulates of VSEPR theory?

Answer 1

Electron pairs (bonding + lone) repel each other.
Molecule adopts shape minimizing repulsion.
Lone pairs repel more than bonding pairs.

Question 2

What is hybridization in chemistry?

Answer 2

Mixing atomic orbitals of similar energy to form new hybrid orbitals with equal energy, shape, and orientation.

Question 3

What are the main postulates of hybridization?

Answer 3

Only orbitals of comparable energy can hybridize.
Hybrid orbitals have different shapes than original orbitals.
Number of hybrid orbitals = number of atomic orbitals mixed.
Hybrid orbitals are oriented to minimize repulsion.
Each hybrid orbital forms one sigma (σ) bond.
Overlapping orbitals must have opposite spins.

Question 4

What rule is used to determine hybridization of the central atom?

Answer 4

Steric number = σ bonds + lone pairs
2 → sp
3 → sp²
4 → sp³
5 → sp³d
6 → sp³d²

Question 5

Describe sp hybridization.

Answer 5

1s + 1p = 2 sp orbitals
50% s, 50% p character
Linear geometry, angle = 180°
Examples: BeCl₂, CO₂, HC≡CH (ethyne), HCN

Question 6

Describe sp² hybridization.

Answer 6

1s + 2p = 3 sp² orbitals
33% s, 67% p
Trigonal planar, angle = 120°
Examples: BF₃, SO₃, C₂H₄

Question 7

Describe sp³ hybridization.

Answer 7

1s + 3p = 4 sp³ orbitals
25% s, 75% p
Tetrahedral, angle = 109.5°
Examples: CH₄, NH₃ (pyramidal), H₂O (bent)

Question 8

Describe sp³d hybridization.

Answer 8

1s + 3p + 1d = 5 hybrid orbitals
Trigonal bipyramidal, angles: 90°, 120°
Examples: PCl₅, PF₅

Question 9

Describe sp³d² hybridization.

Answer 9

1s + 3p + 2d = 6 hybrid orbitals
Octahedral, angle = 90°
Examples: SF₆, [Fe(CN)₆]³⁻

Question 10

If a molecule undergoes sp³ hybridization and has 2 lone pairs, what will be its shape?

Answer 10

Bent (e.g., H₂O)

Question 11

After sp² hybridization in BF₃, what shape does the molecule have?

Answer 11

Trigonal planar with 120° angles.

Question 12

What is the hybridization of N in NH₃?
a) sp²
b) sp³
c) sp

Answer 12

b) sp³ (tetrahedral electron geometry).

Question 13

How do lone pairs affect molecular shape?

Answer 13

Lone pairs occupy more space, reducing bond angles (e.g., H₂O: 104.5° vs. CH₄: 109.5°).

Question 14

Arrange bond angles: NH₃, CH₄, H₂O.

Answer 14

CH₄ (109.5°) > NH₃ (107°) > H₂O (104.5°)

Question 15

A molecule has 2 σ bonds and 0 lone pairs on the central atom. What is its hybridization?

Answer 15

sp → Example: BeCl₂ → Linear (180°)

Question 16

Which hybridization is present in CO₂?
a) sp
b) sp²
c) sp³
d) sp³d

Answer 16

a) sp

Question 17

Why does NH₃ have a pyramidal shape instead of tetrahedral?

Answer 17

One of the four sp³ hybrid orbitals holds a lone pair, so shape becomes trigonal pyramidal.

Question 18

How do hybrid orbitals compare to regular orbitals?

Answer 18

More directional → stronger bonding
Form sigma bonds
Arranged for maximum separation to minimize repulsion