Question

The element of alkaline earth metal which shows a diagonal relationship with aluminium is:

• A. $Mg$
• B. $Ba$
• C. $Be$
• D. $Ca$

Answer 1

The correct option is C $Be$

Option $\left(C\right)$ is correct.

$Be$ shows a diagonal relationship with aluminium.This is due to the similar value of charge/radius ratio and electronegativity. Some of the resemblances are as follows:

1. Unlike groups – 2 elements but like aluminium, beryllium forms covalent compounds.
   
2. The hydroxides of beryllium and aluminium are amphoteric in nature, whereas those of other elements of a group-2 are basic in nature.
   
3. The oxides of both $Be$ and $Ali.e.BeO$ and $A{l}_2{O}_3$ are high melting insoluble solids.
   
4. $BeC{l}_2$ and $AlC{l}_3$ have bridged chloride polymeric structure.