Question

Which of the following overlapping results non-bonding molecular orbitals, if z-axis is considered as internuclear axis?

• A. $p_z+p_z$
• B. $p_y+p_y$
• C. $p_x+s$
• D. $p_y+s$

Answer 1

The correct option is C $p_x+s$

A non-bonding molecular orbital $\left(NBMO\right)$ is a molecular orbital whose occupation by electrons neither increases nor decreases the bond order between the involved atoms. With $p_z$ being an internuclear axis, if an s orbital approaches a p orbital from a different angle (not z-axis) both constructive and destructive interference occurs. So, the gain is the same amount as loss and as a result, no bond can be formed.

$p_x+s$ form non-bonding molecular orbital