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MCQ practice · SSC Chemistry Board questions · Chapter 4: Periodic Table

Barishal Board 2021

In which group of the periodic table is the element 'X' → 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s²?

Think it through first, then pick an option.

  1. a Group-2
  2. b Group-4
  3. c Group-10
  4. d Group-12
Answer and explanation

Correct answer: b Group-4

Rule 3: 3d² plus 4s² gives 2 + 2 = 4 (Ti).

Why the other options are wrong

  • a Group-2: Counting only 4s² gives 2; add the d before it. The answer is Group-4.
  • c Group-10: Group 10 needs 3d⁸4s² (Ni). The answer is Group-4.
  • d Group-12: Group 12 needs 3d¹⁰4s² (Zn). The answer is Group-4.