The first ionization energy is the lowest for · ABC26IN1297
Subject: Inorganic Chemistry · Chapter: Main Group Elements · Topic: Main Group Elements – General · Exam: CSIR NET DEC 2017 · Marks: 2 · Difficulty: Easy
The first ionization energy is the lowest for
(a)Br
(b)Se
(c)P
(d)As
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
IE₁ (kJ mol⁻¹): Se 941 < As 947 < P 1012 < Br 1140; Se is lowest because the paired 4p⁴ electron is easier to remove than the half-filled 4p³ of As.