Question

Which of the following molecule does not have duplet configuration?

• A. Hydride ion
• B. Hydrogen molecule
• C. Lithium cation
• D. $B{e}^{3+}$

Answer 1

The correct option is D $B{e}^{3+}$

$B{e}^{3+}$ does not have duplet configuration.
Duplet configuration is having $\left[He\right]$ configuration, i.e., 2 electrons.
Hydride ion, $H^{-}$ is $1s^2$ contains 2 electrons.
Hydrogen Molecule, $H_2$ contains 2 electrons.
Lithium Cation, $L{i}^{+}$ contains 2 electrons.
Berrilium ion, $B{e}^{+3}$ contains only 1 electron.