Question

What is ionization enthalpy?

Answer 1

Ionization enthalpy:

• “A quantitative measure of the tendency of an element to lose an electron from its valence shell is given by its Ionization Enthalpy(IE).”
• “It is the energy required to remove an electron from the valence shell from an isolated gaseous atom $\left(\mathrm{X}\right)$ in its ground state.”
• The first ionization enthalpy (IE₁ ) for an element $\mathrm{X}$ can be depicted as:

$\mathrm{X}\left(\mathrm{g}\right)\to {\mathrm{X}}^{+}\left(\mathrm{g}\right)+{\mathrm{e}}^{-}$

• The unit of ionization enthalpy is$\mathrm{kJ}{\mathrm{mol}}^{-1}$.
• IE decreases on moving down the group in the periodic table while it increases across the period from left to right.