Physics I / Bonding and molecular geometry
Practice question · Multiple choice

Water is H–O–H, yet the molecule is bent (104.5°), not straight. What bends it?

Hints
  1. Count all electron groups around oxygen: 2 bonds + 2 lone pairs = 4 groups arranged tetrahedrally.
  2. Lone pairs are held closer to the atom and repel harder than bonding pairs, squeezing the H–O–H angle below the tetrahedral 109.5°.
Show the answer

A. Two lone pairs on oxygen push the O–H bonds together

Why

VSEPR: four electron groups adopt a tetrahedron; the two invisible lone pairs claim their corners and shove the bonds together to 104.5°. That bend makes water polar, and water’s polarity underwrites solubility, hydrogen bonding, and life.

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