Which of the following best explains why a water molecule (H_2O) has a bent geometry rather than a linear geometry?

• A. The hydrogen atoms are much larger than the oxygen atom, forcing the molecule to bend.
• B. The bent shape is due to the presence of double bonds between oxygen and hydrogen.
• C. Water forms a bent shape because the oxygen atom has a lower electronegativity than hydrogen.
• D. The two lone pairs of electrons on the oxygen atom repel the hydrogen atoms, causing the molecule to adopt a bent shape.

Answer: (D)

Verified step by step guidance

1. Recall that the shape of a molecule is determined by the arrangement of electron pairs around the central atom, according to the VSEPR (Valence Shell Electron Pair Repulsion) theory.
2. Identify the central atom in the water molecule, which is oxygen, and note that it has two bonded pairs (to hydrogen atoms) and two lone pairs of electrons.
3. Understand that lone pairs of electrons occupy more space than bonding pairs because they are localized closer to the central atom and repel other electron pairs more strongly.
4. Recognize that the repulsion from the two lone pairs on oxygen pushes the hydrogen atoms closer together, resulting in a bent molecular geometry rather than a linear one.
5. Conclude that the bent shape of water is due to the repulsion between the lone pairs and bonding pairs, not because of atom size, bond type, or electronegativity differences.