Question

Select the incorrect overlap if $z$-axis is the inter-nuclear axis:

• A. $2p_y+2p_y\to \pi 2p_y$
• B. $2p_z+2p_z\to \sigma 2p_z$
• C. $2p_x+2p_x\to \pi 2p_x$
• D. $1s+2p_y\to \pi (1s-2p_y)$

Answer 1

The correct option is D $1s+2p_y\to \pi (1s-2p_y)$

$2p_y$ orbitals of an atom overlaps side by side with $2p_y$ orbital of another atom and forms a $\pi$ bond.
$2p_z$ orbitals of an atom overlaps head on with $2p_z$ orbital of another atom and forms a $\sigma$ bond.
$2p_x$ orbitals of an atom overlaps side by side with $2p_x$ orbital of another atom and forms a $\pi$ bond.
1s orbital and $2p_y$ orbital will never form $\pi$ bond since s orbital overlapping always forms a sigma bond.