Question

Rank the elements in each of the following sets in order of increasing first ionization energy. (Use the appropriate <, =, or > symbol to separate substances in the list.)

(a)    Na, H, Li, Rb

(b)    C, B, F, N

Answer 1

solution:

(a) Na, H, Li, Rb

As we know that in periodic table on going down in a group, the first Ionisation energy decreases since size of element increases.

Hence the order of increasing first ionization energy will be - Rb<Na<Li<H

(b)  C, B, F, N

As we know that in periodic table on going along the periode, the first Ionisation energy increases since size of element decreases.

Hence the order of increasing first ionization energy will be- B<C<N<F