Question

Arrange the following as per the instructions given in the brackets.

$\mathrm{Na},\mathrm{K},\mathrm{Cl},\mathrm{S},\mathrm{Si}$ (increasing order of ionization energy).

Answer 1

• Ionization energy: It is the amount of energy required to remove an electron from the isolated gaseous atom of an element.
• Ionization energy increases across the period and decreases down the group.
• As we go down the group, the size of the atom increases and the force of attraction between the electrons and the nucleus decreases, and an electron can be removed easily.
• Ionization enthalpy of elements decreases as we move down in a group, down in a group the atomic number increases and the number of shells also increases.
• 

Hence the increasing order of ionization energy is$\mathrm{K}<\mathrm{Na}<\mathrm{Si}<\mathrm{S}<\mathrm{Cl}$.