Question

Which of the following hybrid atomic orbitals would you consider most useful for approximating a molecular orbital scheme around the boron atom in BF3?
Select one:

a. sp3

b. 2s and 2p

c. sp2

d. sp

Answer 1

Answer:

$Option\;(c)\;sp^2$

Explanation:

Atomic number of boron = 5

In ground state,

Valence shell electronic configuration of B = $2s^2\;2p^1$

In excited state, one 2s electrons goes into vacant 2p orbital and electronic configuration becomes: $2s^1\;2p^2$

Now, 3 orbitals (2s, and two orbitals of 2p) of B have unpaired electrons. These three orbitals (one 2s, and two orbitals of 2p) undergoes hybridisation to form three hybridised sp2 orbitals.

These 3 hybridised sp2 orbitals are oriented in a trigonal planar arrangement.

The  three hybridised sp2 orbitals overlap with 2p orbital of three F to form three B-F bonds.