Question

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

• A. Li < B < Be < C < N < O < F < Ne
• B. Li< Be < B < C < O < N < F < Ne
• C. Li < Be < B < C < N < O < F < Ne
• D. Li < B < Be < C < O < N < F < Ne

Answer 1

The correct option is D Li < B < Be < C < O < N < F < Ne

As we go from left to right in a period ionisation energy increases. ′Be′ and ′N′ comparatively more stable valence subshell than 'B' and 'O'.

Hence, the correct order of first ionisation enthalpy is:

$Li<B<Be<C<O<N<F<Ne$