Water has a 'bent' molecular geometry. Which properties of water contribute to this shape?

• A. The presence of two lone pairs on the oxygen atom
• B. The absence of lone pairs on the oxygen atom
• C. The linear arrangement of hydrogen atoms
• D. The equal sharing of electrons between hydrogen and oxygen

Answer: (A)

Verified step by step guidance

1. Understand the concept of molecular geometry: Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. The shape is determined by the number of bonding pairs and lone pairs of electrons around the central atom.
2. Identify the central atom in a water molecule: In H₂O, the central atom is oxygen, which is bonded to two hydrogen atoms.
3. Consider the electron pair geometry: Oxygen has six valence electrons, two of which are used to form bonds with hydrogen atoms, leaving two lone pairs of electrons.
4. Apply the VSEPR theory: According to the Valence Shell Electron Pair Repulsion (VSEPR) theory, electron pairs around a central atom will arrange themselves to minimize repulsion. The two lone pairs on oxygen repel the bonding pairs, resulting in a bent shape.
5. Conclude the effect of lone pairs: The presence of two lone pairs on the oxygen atom causes the H-O-H bond angle to be less than 109.5°, leading to the bent shape of the water molecule.