How do the following properties change in group - 1 and in the third period? Explain with example.
(b) IE

Explanation

Ionization energy: In a group ionization energy values decreases with an increase in the size of the atom. In IA group Li is the element with highest ionization potential and Cs is the element with lowest ionization potential.
In third period the ionization potential increases From Na to Mg and then decreases at Al and increases upto P and decreases in case of S and then increases upto argon i.e., Al has a lower value than Mg and S has a lower value than P, due to stable electronic configurations of Mg and P Among these elements argon has highest ionization potential.