Question

Elements with lowest and highest I.P. values in each period respectively are :

• A. alkali metals, noble gases
• B. alkali metals, halogens
• C. halogens, alkali metals
• D. noble gases, alkali metals

Answer 1

The correct option is A alkali metals, noble gases

In a period, as we move from left to right, the ionization energy increases. As we move along a period, the nuclear charge increases and the electrons are added into the same shell. Thereby the effective nuclear charge increases and size decreases. Therefore, the energy required to remove an electron increases.
Thus, alkali metals have the lowest I.P. and noble gases have the highest I.P.