Question

Arrange the elements of the second and third period in increasing order of ionization energy.

Answer 1

• As the ionization energy increases on moving from left to right in a period as the nuclear charge increases.

Order of ionization energy of the elements of the second period:

$Li<B<Be<C<O<N<F<Ne$.

Order of ionization energy of the elements of the third period:

$Na<Al<Mg<Si<S<P<Cl<Ar$.

Exceptions are there in elements in period 2 and 3.