Question 7 — Which of the following, in - Questions at the end of the chapter - Chapter 9 - Atomic Foundations of Matter (Exploration)

Last updated at July 20, 2026 by

Question 7
Which of the following, in Fig. 9.18, correctly represents Cl⁻ ion (Atomic number of chlorine = 17).
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  • Cl⁻ has gained one electron: 17 + 1 = 18 electrons .
  • Configuration must be 2, 8, 8 (a complete octet).
  • The correct diagram is the one showing shells filled as 2, 8, 8.
Diagram (Fig. 9.18)
Electron count → verdict
(i)
Shows 17 electrons (2, 8, 7) — Wrong . That is a neutral Cl atom.
(ii)
Shows 18 electrons (2, 8, 8) — Correct . Cl⁻ gains one electron.
(iii)
Electron count does not give a complete octet — Wrong .
(iv)
Only 2, 8 shells shown — Wrong . Too few electrons for chlorine.
Back to: 9.4.2 Bonding by electron transfer — Ionic bond
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