The angle between the hydrogen atoms in water (H2O) is slightly less than expected for a tetrahedral shape. This is because of the

Oxygen in water has two bonding pairs and two lone pairs of electrons. Lone pairs repel the bonding pairs more strongly than bonding pairs repel each other, pushing the O–H bonds closer together and making the angle slightly smaller than the tetrahedral angle of 109.5°. So the correct choice is extra electron repulsion from the lone pairs.

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