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For a trigonal bipyramidal (TBP) arrangement AX5, which placement is favored for the two larger ligands Y in AX3Y2?

Equatorial positions to minimize 90° repulsions; the smaller X occupy axial sites.

Axial positions because longer axial bonds avoid steric crowding.

Placement is irrelevant; all TBP positions experience the same 90° interactions.

One axial and one equatorial to maximize symmetry.

XeF4 has how many lone pairs on xenon and what molecular shape?

One lone pair; square pyramidal.

Three lone pairs; T‑shaped.

Two lone pairs; square planar.

No lone pair; tetrahedral.

Which statement about hypervalent bonding in SF6 is closest to modern understanding?

Sulfur uses unhybridized p orbitals only.

Octahedral geometry in SF6 violates the octet rule and is impossible.

Bonding is well described by delocalized 3c–4e interactions and ionic contributions; explicit d‑orbital participation on S is minor.

Six equivalent sp3d2 hybrids on sulfur are required and dominate bonding.

Which pair has the correct geometry and approximate angle?

NO2 (radical): perfectly linear (180°).

NO2−: linear; NO2+: bent.

NO2+: bent with ~130°.

NO2−: bent (~120°); NO2+: linear (180°).

The shape of ICl2− is:

Trigonal planar.

Bent with two lone pairs.

T‑shaped.

Linear with three lone pairs on iodine.

Among H2O, OF2, and NH3, which has the smallest bond angle?

H2O

OF2

All equal (~109.5°).

NH3

Which molecule is nonpolar despite polar bonds?

CCl4

SO2

NH3

CH2Cl2

Which statement about equivalence of hybrid orbitals is correct?

Equivalence holds whenever the steric number is 4, regardless of substituents.

In PH3, three P–H hybrids have more s‑character than the lone pair.

In CH4, all four hybrids are equivalent; in NH3 and H2O, one or two hybrids (lone pairs) have greater s‑character than the bonding hybrids.

In CH3F, all four hybrids are strictly identical due to tetrahedral geometry.

Chemistry — Unit 1 — Test 3