Question

On moving across a period from left to right the ionisation energy increases because:

• A. value of principal quantum number increases
• B. effective nuclear charge increases
• C. atomic size increases
• D. nuclear charge increases

Answer 1

The correct option is D nuclear charge increases

As we move towards the right the nuclear charge increases in the period. Thus it becomes difficult to remove an electron as it is strongly attracted. Thus the IE increases towards the right. Hence correct answer is option D.