Consider the structural description: 'A central atom bonded to three peripheral atoms, with exactly one lone pair of electrons on the central atom.' Which of the following pairs of species both perfectly match this description?

Step-by-step solution

To match the description, the central atom must have 3 bond pairs and 1 lone pair. For SO ₃²⁻ and CO ₃²⁻ : SO ₃²⁻ has 6 + 3(6) + 2 = 26 valence electrons (3 bond pairs, 1 lone pair). CO ₃²⁻ has 4 + 3(6) + 2 = 24 valence electrons (3 bond pairs, 0 lone pairs). For BF ₃ and NO ₃⁻ : Both have 24 valence electrons, resulting in 3 bond pairs and 0 lone pairs on the central atom (trigonal planar geometry). For ClO ₃⁻ and PCl ₃ : ClO ₃⁻ has 7 + 3(6) + 1 = 26 valence electrons. PCl ₃ has 5 + 3(7) = 26 valence electrons. Bo