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NEET Chemistry
QUESTION #7421
Question 1
If the ionisation potentials of Na, Mg, and Si are 496, 737, and 786 kJ/mol respectively, then the IP of Al is approximately:
Correct Answer Explanation
Al (Z=13): configuration [Ne] 3s² 3p¹
Al's IE₁ is lower than Mg (3s² full shell, extra stability) and lower than Si (3p² — removing one from paired is easier, but Si is to the right with higher Z*).
Experimentally, IE₁ of Al ≈ 577 kJ/mol. This lies between Na (496) and Mg (737), confirming the anomaly: Al has lower IE₁ than Mg despite being to its right in the period.
Al's IE₁ is lower than Mg (3s² full shell, extra stability) and lower than Si (3p² — removing one from paired is easier, but Si is to the right with higher Z*).
Experimentally, IE₁ of Al ≈ 577 kJ/mol. This lies between Na (496) and Mg (737), confirming the anomaly: Al has lower IE₁ than Mg despite being to its right in the period.
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