Question

Molecule having maximum number of lone pairs of electrons on central atom is:

• A. $P{H}_3$
• B. $H_{2}S$
• C. $C{H}_4$
• D. $Br{F}_5$

Answer 1

The correct option is B $H_{2}S$

$P$ belongs to group $5$ and has $5$ electrons in valence shell. $3$ are involved in bonding with the $3$ $H$ atoms. So, lone pair $=1$.
$S$ belongs to group $16$ and has $6$ electrons in valence shell. $2$ are involved in bonding with the $2$ $H$ atoms. So, lone pairs $=2$.
$C$ belongs to group $14$ and has $4$ electrons in valence shell. $4$ are involved in bonding with the $4$ $H$ atoms. So, lone pair $=0$.
$Br$ belongs to group $17$ and has $7$ electrons in valence shell. $5$ are involved in bonding with the $5$ $F$ atoms. So, lone pair $=1$.