What is the anomalous behaviour of beryllium ?

Explanation

The anomalous behaviour of beryllium is given below:
(i) Beryllium has exceptionally small atomic size. Because of small size, it has high ionisation enthalpy.
(ii) Due to absence of d-orbital, its coordination number is not more than four.
(iii) The oxides and hydroxides of beryllium are amphoteric (metallic as well as non metallic) in nature.