Which pair of elements will form a covalent bond?
a. hydrogen and chlorine
b. sodium and chlorine
c. copper and bromine
d. zinc and bromine

Option (A) is the correct answer.

Explanation:

A covalent bond is formed when there occurs sharing of electrons between atoms.

For example, in hydrogen atom there is one electron in its orbit and in a chlorine atom there is 7 valence electron. So, in order to attain stability both hydrogen and chlorine share electrons when they come close to each other.

Whereas except hydrogen and chlorine rest of the given atoms will form ionic bond, that is, bond formed by transfer of electrons.

Thus, we can conclude that a pair of hydrogen and chlorine will form a covalent bond.

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