passwella.
Menu

Unilorin Post-UTME Chemistry 2021 (Model questions) Question 5

Question 5

Atomic Structure

Which of the following pairs of species contains the same number of electrons? [6C, 8O, 10Ne, 11Na, 12Mg, 13Al, 17Cl]

  1. A.Mg2+ and Al3+
  2. B.Cl− and Ne
  3. C.Na+ and Mg
  4. D.C and O2−
Show the answer and explanation

Answer: A (Mg2+ and Al3+)

Explanation

Mg2+ has 12 − 2 = 10 electrons and Al3+ has 13 − 3 = 10 electrons.