Question

Find the sum of the total number of $P-\hat{P}-P$ angle and $P-P$ sides in $P_4$ molecule.

Answer 1

$P_4$ molecule has pyramidal geometry. It has $6P-P$ sides. Therefore, the number of $P-P-P$ angles is 12. Hence, the sum of $P-\hat{P}-P$ angle and $P-P$ sides in a $P_4$ molecule is $6+12=18$.