For the second period elements the correct increasing order of first ionization enthalpy is

Question : For the second period elements the correct increasing order of first ionization enthalpy is :

(1) Li <  Be < B < C < N < O< F <  Ne

(2) Li < B < Be < C< O < N < F <  Ne

(3) Li < B < Be < C < N < O < F <  Ne

(4) Li < Be < B < C< O < N < F  < Ne

Answer : from all above options the correct answer is “(2) Li < B < Be < C< O < N < F <  Ne ” and the reason behind this answer is given below –

The effective nuclear charge (Z_eff) increases in a period, hence IE increases. Hence, the correct order of increasing ionization energy is Li < B < Be < C < O < N < F < Ne.