Question

Which ionisation potential (IP) in the following equations involves the greatest amount of energy?

• A. $Na\to N{a}^{+}+e^{-}$
• B. $K^{+}\to K^{2+}+e^{-}$
• C. $C^{2+}\to C^{3+}+e^{-}$
• D. $C{a}^{+}\to C{a}^{2+}+e^{-}$

Answer 1

The correct option is C $C^{2+}\to C^{3+}+e^{-}$

Electronic Configuration of $C^{2+}\to {1s}^2{2s}^2$

Electronic Configuration of $K^{+}\to {1s}^2{2s}^2{2p}^6{3s}^2{3p}^6$

Electronic Configuration of $Na\to {1s}^2{2s}^2{2p}^6{3s}^1$

Electronic Configuration of ${Ca}^{+}\to {1s}^2{2s}^2{2p}^6{3s}^2{3p}^6{4s}^1$

as ${1s}^2{2s}^2$ i.e. $C^{2+}$ has highest z effective. To remove an electron from ${2s}^2$ higher energy is needed than in case of others. Also it is the third ionization enthalpy of carbon.

Thus $C^{2+}⟶C^{3+}+e^{-}$will have highest Ionization potential.