JEE Main · 2022 · Shift-IeasyBOND-071

Number of lone pairs of electrons in the central atom of SCl2, O3, ClF3 and SF6, respectively, are

Chemical Bonding · Class 11 · JEE Main Previous Year Question

Question

Number of lone pairs of electrons in the central atom of SCl2\mathrm{SCl_2}, O3\mathrm{O_3}, ClF3\mathrm{ClF_3} and SF6\mathrm{SF_6}, respectively, are

Options
  1. a

    0, 1, 2 & 2

  2. b

    2, 1, 2 & 0

  3. c

    1, 2, 2 & 0

  4. d

    None of these

Correct Answerb

2, 1, 2 & 0

Detailed Solution

🧠 Count lone pairs on the central atom of each molecule: LP = (valence e of central − bonds made)/2.

| Molecule | Central | Valence e | Bonds | LP | |---|---|---|---|---| | \ceSCl2\ce{SCl2} | S | 6 | 2 | (6−2)/2 = 2 | | \ceO3\ce{O3} | O | 6 | 2 | (6−2)/2 = 1 (one double bond + one single bond) | | \ceClF3\ce{ClF3} | Cl | 7 | 3 | (7−3)/2 = 2 | | \ceSF6\ce{SF6} | S | 6 | 6 | (6−6)/2 = 0 |

⚠️ Trap for \ceO3\ce{O3}: central O has 1 LP (despite looking like it should have 2). It uses 4 electrons in bonds (1 double + 1 single) and keeps 2 as a lone pair — steric number 3 → sp² bent.

Answer: (b) 2, 1, 2, 0\boxed{\text{Answer: (b) 2, 1, 2, 0}}

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Number of lone pairs of electrons in the central atom of SCl2, O3, ClF3 and SF6, respectively, are (JEE Main 2022) | Canvas Classes