Question

Which of the following is not a correct statement?

• A. $s-$block elements, except $Be$ and $Mg$, form ionic hydrides
• B. Interstitial hydrides are non-stoichiometric in nature
• C. $p-$block elements form covalent hydrides
• D. $d$ and $f-$block elements form ionic hydrides

Answer 1

The correct option is D $d$ and $f-$block elements form ionic hydrides

Ionic hydrides are formed when hydrogen reacts with highly electropositive $s-$block elements except $Be$ and $Mg$ (alkali metals and alkaline earth metals).

Covalent hydrides are compounds of hydrogen and non-metals due to their similarity in electronegativity. As non-metals are present in $p-$block, hence $p-$block elements form covalent hydrides.

Interstitial hydrides are formed when hydrogen molecule reacts with the $d$ and $f-$ block elements. These are usually formed by transition metals and are mostly non-stoichiometric, which means the fraction of $H-$atoms to the metals are not fixed.