Question

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

• A. La < B < Be < C < N < O < F < Ne
• B. Li< Be < B < C < 0 < N < F < Ne
• C. Li < Be < B < C < N < O < F < Ne
• D. Li < B < Be < C < O < N < F < Ne

Answer 1

Answer: (D)

‘Be’ and ‘N’ have comparatively more stable valence sub-shell than ‘B’ and ‘O’.
$\therefore$ Correct order of first ionisation enthalpy is:
Li < B < Be < C < O < N < F < Ne