Which from following molecules has two lone pair of electrons in valence shell of its central atom?
Which from following molecules has two lone pair of electrons in valence shell of its central atom?
$\mathrm{SO}_2$
$\mathrm{NH}_3$
$\mathrm{H}_2 \mathrm{O}$
$\mathrm{SF}_4$
Solution
In $\mathrm{H}_2 \mathrm{O}$, central atom oxygen ( 6 valence electrons), attains a stable octet by bonding with 2 hydrogen atoms, resulting in 2 bond pairs and 2 lone pairs (four non-bonding electrons).