Question

The correct order of increasing ionisation energy of Be, Mg, Ca, Sr is ______.

Options

• Be, Mg, Ca, Sr

• Ca, Mg, Be, Sr

• Sr, Ca, Mg, Be

• Mg, Ca, Sr, Be

Answer 1

The correct order of increasing ionisation energy of Be, Mg, Ca, Sr is Sr, Ca, Mg, Be.

Explanation:

These elements are in group 2. Ionisation energy decreases down a group as atomic size and the distance of the outer electrons from the nucleus increase, so the increasing order is Sr, Ca, Mg, Be.