Which of the following electronegativity order is incorrect?

We need to find which electronegativity order is incorrect.

Key electronegativity values (Pauling scale):

• Mg = 1.31, Be = 1.57, B = 2.04, N = 3.04
• Al = 1.61, Si = 1.90, C = 2.55
• S = 2.58, Cl = 3.16, O = 3.44, F = 3.98

Option A: Mg < Be < B < N. 1.31 < 1.57 < 2.04 < 3.04 ✓ (Correct order)

Option B: S < Cl < O < F. 2.58 < 3.16 < 3.44 < 3.98 ✓ (Correct order)

Option C: Al < Si < C < N. 1.61 < 1.90 < 2.55 < 3.04 ✓ (Correct order)

Option D: Al < Mg < B < N. Claimed: Al (1.61) < Mg (1.31)? But 1.61 > 1.31, so Mg < Al, not Al < Mg. This order is INCORRECT. ✗

The incorrect electronegativity order is Option D: Al < Mg < B < N. The correct order should be Mg < Al < B < N. Therefore, the answer is Option D.