Water (H₂O), a basic molecule, can have its structure elucidated via VSEPR theory (Valence Shell Electron Pair Repulsion theory). The analysis proceeds as follows:
1. Lewis Structure:
- Oxygen contributes 6 valence electrons, and each hydrogen atom contributes 1. In H₂O, oxygen forms two single covalent bonds with the hydrogen atoms, leaving two lone pairs of electrons.
2. Electron Geometry:
- The oxygen atom is surrounded by 4 electron pairs: 2 involved in bonding with hydrogen and 2 as lone pairs. VSEPR theory dictates that these 4 electron pairs orient themselves in a tetrahedral arrangement to minimize inter-pair repulsion.
3. Molecular Geometry:
- Lone pairs, while influencing geometry, are not outwardly part of the molecular structure. Their presence exerts repulsion on the bonding pairs, resulting in a bent molecular configuration.
- The bond angle between the hydrogen-oxygen-hydrogen atoms is approximately 104.5°, deviating from the ideal tetrahedral angle (109.5°) due to the repulsive forces exerted by the lone pairs.
4. Conclusion:
- The water molecule exhibits a bent molecular geometry.