Question

Beryllium and aluminium exhibit many properties which are similar. But the two elements differ in

Answer 1

As we learnt in

Diagonal relationship -

Similarity in properties between first element of a group and second element of the next group

- wherein

This is due to similarity in sizes of their ions, and charge / radius ratio

 

and  

 

 

Anomalous behavious beryllium -

1) Due to small atomic and ionic size

2) High ionisation energy

3) No vacant d-orbitals

4) High hydration energy

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Due to diagonal relationship  Be and Al exhibit many similar properties but covalency of Be is 4 because it has an absence of d-orbital whereas, covalency of Al is up to 6 due to the presence of vacant d-orbital