Question

Which of the following is covalent?
(A) H2
(B) CaO
(C) KCl
(D) Na2S​

Answer 1

Answer:

Na2S

Explanation:

may be H2 is colavent

Answer 2

Answer:

(A)H2

Explanation:

in covalent bond sharing of electrons takes place, that means the valance electrons belong to both the atoms.

so here,

hydrogen(H) has one electon, so two hydrogens share their electron to get Helium electronic configuration which is stable. so in this case the electrons of one hydrogen also belongs to the other, so it means they are sharing their electrons. so H2 is covalent. But in case of B,C and D

they form ionic bonds, they don't share their electrons instead they donate to get octet configuration.