Question

Beryllium differs from the rest of the members of its family (Group IIA) in many ways. The reason for this is
A. Small size and higher electronegativity
B. Small size and lower electronegativity
C. Large size and lower ionisation energy
D. Large size and larger ionic radius

Answer 1

Hint: Beryllium is an element from the group-2 periodic table.
It is the first element of the group so it possesses anomalous behaviour as contradicted to other metals of the exact group.

Complete Step by Step Answer:
Beryllium is a metal of group 2 and has anomalous behaviour.

From the given options we have to find the reason for its anomalous behaviour.
A. Small size and higher electronegativity
Beryllium is the first member of group-2 metals.
We know that size increases down the group due to the addition of electrons to higher energy levels or shells.
So, Be has an extremely small atomic radius and ionic sizes.
Group-2 metals in general have low electronegativity. They are electropositive.
Among the alkaline metals, Be has the higher electronegativity.
This is due to the small size of the cation formed by this metal will distort the electron cloud of the anion more effectively.
So, A is incorrect.

B. Small size and lower electronegativity
Be has a small size and higher electronegativity.
So, B is incorrect.

C. Large size and lower ionisation energy
Be does not have a large size or lower ionisation energy.
So, C is incorrect.

D. Large size and larger ionic radius
Be does not have a large size or larger ionic radius.
So, C is incorrect.

So, option A is correct.

Note: The other anomalous behaviour of Be includes high melting point, hardness, no reaction with air or acids, etc. Beryllium sulphate is soluble in water while sulphates of other metals are either sparingly soluble or insoluble in water.