Question

Which one of the following elements has the highest ionisation energy?

• A. $ [Ne]\,3{{s}^{2}}3{{p}^{1}} $
• B. $ [Ne]\,3{{s}^{2}}3{{p}^{2}} $
• C. $ [Ne]\,3{{s}^{2}}3{{p}^{3}} $
• D. $ [Ar]\,3{{d}^{10}},\,4{{s}^{2}}4{{p}^{2}} $

Answer 1

Answer: (C)

The energy required to remove an electron from the outermost orbit of an atom is known as ionization energy. $ {{P}_{15}}=[Ne]\,3{{s}^{2}}3{{p}^{3}} $ The outermost p subshell of phosphorus is half filled and half-filled orbitals are more stable. Therefore, it is comparatively difficult to remove the electrons from half-filled subshell.