# What is the electron configuration of nitrogen monoxide?

##### 1 Answer

#(sigma_(1s))^2(sigma_(1s)^"*")^2(sigma_(2s))^2(sigma_(2s)^"*")^2(pi_(2p_x))^2(pi_(2p_y))^2(sigma_(2p_z))^2(pi_(2p_x)^"*")^1#

This requires that we know what the **molecular orbital** (MO) **diagram** is for *Miessler et al., Answer Key*):

(The original was this; I added the orbital depictions and symmetry labels.)

Quick overview of what the labels correspond to what MOs:

#1a_1# is the#sigma_(2s)# bonding MO.#2a_1# is the#sigma_(2s)^"*"# antibonding MO.#1b_1# is the#pi_(2p_x)# bonding MO.#1b_2# is the#pi_(2p_y)# bonding MO.#3a_1# is the#sigma_(2p_z)# bonding MO, but it's relatively nonbonding with respect to oxygen.#2b_1# is the#pi_(2p_x)^"*"# antibonding MO.#2b_2# is the#pi_(2p_y)^"*"# antibonding MO.#4a_1# is the#sigma_(2p_z)^"*"# antibonding MO.

As a further note, the **molecular electron configuration** would be written in a similar manner as the atomic counterpart, but using molecular orbitals instead.

We obtain:

#color(blue)((sigma_(1s))^2(sigma_(1s)^"*")^2(sigma_(2s))^2(sigma_(2s)^"*")^2(pi_(2p_x))^2(pi_(2p_y))^2(sigma_(2p_z))^2(pi_(2p_x)^"*")^1)#

Or, another way to write this is in the notation seen in the MO diagram, with

#overbrace(color(blue)(KK_(sigma)))^((sigma_(1s))^2(sigma_(1s)^"*")^2)underbrace(color(blue)((1a_1)^2(2a_1)^2))_((sigma_(2s))^2(sigma_(2s)^"*")^2)overbrace(color(blue)((1b_1)^2(1b_2)^2))^((pi_(2p_x))^2(pi_(2p_y))^2)overbrace(color(blue)((3a_1)^2))^((sigma_(2p_z))^2)underbrace(color(blue)((2b_1)^1))_((pi_(2p_x)^"*")^1)#