Question

A species has the following MO configuration: (σ1s)2(σ1s*)2(σ2s)2(σ2s*)2(σ2p)2(π2p)2. This substance is:_______.

a. paramagnetic with two unpaired electrons.
b. diamagnetic paramagnetic with three unpaired electrons.
c. paramagnetic with four unpaired electrons.
d. paramagnetic with one unpaired electron.

Answer 1

Answer : The correct option is, (a) paramagnetic with two unpaired electrons.

Explanation :

According to the molecular orbital theory, the general molecular orbital configuration will be,

`(\sigma_(1s)),(\sigma_(1s)^*),(\sigma_(2s)),(\sigma_(2s)^*),(\sigma_(2p_z)),[(\pi_(2p_x))=(\pi_(2p_y))],[(\pi_(2p_x)^*)=(\pi_(2p_y)^*)],(\sigma_(2p_z)^*)`

As there are 14 electrons present in the given configuration.

The molecular orbital configuration of molecule will be,

`(\sigma_(1s))^2,(\sigma_(1s)^*)^2,(\sigma_(2s))^2,(\sigma_(2s)^*)^2,(\sigma_(2p_z))^2,[(\pi_(2p_x))^1=(\pi_(2p_y))^1],[(\pi_(2p_x)^*)^0=(\pi_(2p_y)^*)^0],(\sigma_(2p_z)^*)^0`

The number of unpaired electron in the given configuration is, 2. So, this is paramagnetic. That means, more the number of unpaired electrons, more paramagnetic.

Hence, the correct option is, (a) paramagnetic with two unpaired electrons.