Question

Beryllium and aluminium exhibit many properties which are similar. But, they differ in:

• A. Forming covalent halides
• B. Forming polymeric hydrides
• C. Exhibiting maximum covalency in compounds
• D. Exhibiting amphoteric nature in their oxides

Answer 1

The correct option is C Exhibiting maximum covalency in compounds

Due to diagonal relationship, $Be$ and $Al$ have many similar properties. However, they differ in exhibiting maximum covalency.
Maximum covalency of $Be=4$
Maximum covalency of $Al=6$
This is due to the absence of $d$-orbitals in $Be$.