Question

B2 molecule will be diamagnetic when​

Answer 1

B

2

molecule has no. of electrons =10

Molecular orbital configuration:

σ(1s)

2

σ

∗

(1s)

2

σ(2s)

2

σ

∗

(2s)

2

π2p

x

1

π2p

y

1

Due to unpaired electron, it is paramagnetic.

The highest occupied MO is of π- type.

Hence, both the assertion and reason are false.

Answer 2

Answer:

$B_2$ is paramagnetic because it has two unpaired electrons, one in each of its p orbitals.

Explanation:

In $B_2$, total number of electrons = 10

$B_{2} \rightarrow \sigma(1 s)^{2} \sigma^{*}\left(1 s^{2}\right) \sigma(2 s)^{2} \sigma^{*}(2 s)^{2} \sigma\left(2 p_{x}\right)^{1} \pi\left(2 p_{y}\right)^{1}$

The presence of an unpaired electron demonstrates the paramagnetic nature.

The most occupied molecular orbital is of the -type.