Question

The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound.

HS2

HS

H4S

H2S

Answer 1

Sulfur has 6 valence electrons and needs 2 more electrons to complete its valence shell (octet rule). Each hydrogen atom has 1 valence electron and can form one covalent bond. To satisfy the valence requirements of sulfur, two hydrogen atoms will combine with one sulfur atom.

Thus, the correct molecular formula for hydrogen sulfide is **H₂S**.