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Difficulty: Very hardMolecular Shapes, VSEPR Theory, and Hybridization

Match each of the following chemical species on the left with its corresponding central atom hybridization state and molecular geometry on the right, as predicted by Valence Shell Electron Pair Repulsion (VSEPR) theory. Which set of pairs accurately connects each species to its geometry and hybridization?

  • Iodine trifluoride (IF3IF_3)sp3dsp^3d hybridization with T-shaped molecular geometry
  • Pentafluoroxenate ion (XeF5−XeF_5^-)sp3d3sp^3d^3 hybridization with pentagonal planar molecular geometry
  • Sulfite ion (SO32−SO_3^{2-})sp3sp^3 hybridization with trigonal pyramidal molecular geometry
  • Nitronium ion (NO2+NO_2^+)spsp hybridization with linear molecular geometry

Answer

Iodine trifluoride (IF3IF_3) matches with sp3dsp^3d hybridization and T-shaped geometry; Pentafluoroxenate ion (XeF5−XeF_5^-) matches with sp3d3sp^3d^3 hybridization and pentagonal planar geometry; Sulfite ion (SO32−SO_3^{2-}) matches with sp3sp^3 hybridization and trigonal pyramidal geometry; Nitronium ion (NO2+NO_2^+) matches with spsp hybridization and linear geometry.
Each chemical species is correctly paired according to its total steric number (sum of bonding electron domains and non-bonding lone pairs). IF3IF_3 has steric number 5 (sp3dsp^3d, T-shaped), XeF5−XeF_5^- has steric number 7 (sp3d3sp^3d^3, pentagonal planar), SO32−SO_3^{2-} has steric number 4 (sp3sp^3, trigonal pyramidal), and NO2+NO_2^+ has steric number 2 (spsp, linear).

Step-by-Step Solution

1
Determine valence electron count and steric number for IF3IF_3
Iodine has 7 valence electrons + 3 from fluorine = 10 electrons (5 pairs). Steric number = 5 (3 bonding pairs, 2 lone pairs).
Steric number 5 corresponds to sp3dsp^3d hybridization. Two equatorial lone pairs force the 3 terminal fluorines into a T-shaped arrangement.
2
Determine valence electron count and steric number for XeF5−XeF_5^-
Xenon has 8 valence electrons + 5 from fluorine + 1 from overall negative charge = 14 electrons (7 pairs). Steric number = 7 (5 bonding pairs, 2 lone pairs).
Steric number 7 corresponds to sp3d3sp^3d^3 hybridization. The two lone pairs occupy axial positions above and below the equatorial plane, creating a pentagonal planar molecular shape.
3
Determine valence electron count and steric number for SO32−SO_3^{2-}
Sulfur has 6 valence electrons + 2 from charge = 8 valence shell electrons. It forms 3 sigma bonds with oxygen and retains 1 lone pair. Steric number = 4.
Steric number 4 corresponds to sp3sp^3 hybridization. Three bonding domains and 1 lone pair produce a trigonal pyramidal molecular shape.
4
Determine valence electron count and steric number for NO2+NO_2^+
Nitrogen has 5 valence electrons - 1 from positive charge = 4 electrons. It forms two double bonds with oxygen atoms and has 0 lone pairs. Steric number = 2.
Steric number 2 corresponds to spsp hybridization, resulting in a linear geometry with a 180∘180^\circ bond angle.

Key Concept

VSEPR Theory, Steric Numbers, and Central Atom Hybridization States
Estimated Time:2m 30s
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Topics

Molecular Shapes, VSEPR Theory, and Hybridization

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