Which of the following pairs of molecule can exist ?

CHEMISTRY · Single correct · CBSE · Chemistry · Chemical Bonding and Molecular Structure · Chemical Bonding and Molecular Structure

Problem

Which of the following pairs of molecule can exist ? (1)

He_2

and

Be_2

(2)

O_2^{2-}

and

Na_2

(3)

O_2^{2-}

and

H_2^-

(4)

Be_2

and

Mg_2