Question

Arrange Be, Ca, Ba, Ra in increasing order of ionisation energy:

• A. Be < Ra < Ca < Ba
• B. Ba < Ca < Ra < Be
• C. Ra < Ba < Ca < Be
• D. Ba < Ra < Ca < Be

Answer 1

The correct option is C Ra < Ba < Ca < Be

Atomic number of Beryllium - 4

Atomic number of Calcium - 20

Atomic number of Barium - 56

Atomic number of Radium – 88

From the atomic numbers, we can easily say that Beryllium is the starting element in II A group and Radium is the last element in II A group.

We know that as we are moving from top to bottom in the periodic table the atomic size of the atoms increases.

So, the increasing order of ionization energy of given elements is as follows.

Ra < Ba < Ca < Be

Hence, option C is correct.