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JAMB Chemistry 2020 Objective — Question 6

Question 6 of 40 from the Joint Admissions and Matriculation Board (JAMB) Chemistry 2020 Objective paper, with the correct answer and a full explanation.

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6. An ion X+ has 14 electrons. How many unpaired electrons are there in the neutral atom of X?

  • A. A. 4
  • B. B. 3Correct
  • C. C. 2
  • D. D. 1

Explanation

If X+ has 14 electrons, neutral X has 15 electrons: 1s2 2s2 2p6 3s2 3p3. The 3p3 configuration has 3 unpaired electrons (Hund's rule).

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