If the first ionisation enthalpy of Li , Be and C respectively are 520,899,1086 ~kJ ~mol ⁻¹ , the first ionisation enthalpy (in kJ mol ⁻¹ ) of B will be

Step-by-step solution

First ionisation enthalpy of Li , Be and C respectively are 520,899,1086 ~kJ ~mol ⁻¹ . The ionisation energy depend on the (i) Size of the atom (ii) effective nuclear charge (iii) Screening effect (iv) Penetration effect (v) Electronic configuration aligned & Li -1 ~s ^2 2 ~s ^1 & Be -1 ~s ^2 2 ~s ^2 & ~B -1 ~s ^2 2 ~s ^2 2 p ^1 & C -1 ~s ^2 2 ~s ^2 2 p ^2 aligned (i) Left to right in the periodic table ionisation enthalpy increase. (ii) Beryllium have full filled orbital so its ionisation energy is more than boron