Why is water polar?

📌 CONCEPT: Water is polar due to its bent or V-shape molecular geometry, resulting in a distribution of electrons that creates a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom.

📐 RULE / FORMULA: According to the VSEPR (Valence Shell Electron Pair Repulsion) theory, the shape of a molecule is determined by the repulsion between electron pairs in the valence shell of the central atom.

💡 WORKED EXAMPLE: For example, when a water molecule (H2O) is formed, the oxygen atom has two lone pairs of electrons and two hydrogen atoms bonded to it. Applying VSEPR theory, we find that the shape of the water molecule is bent or V-shaped, resulting in a polar molecule with partial positive and negative charges.

⚠️ COMMON MISTAKE: Students often mistake water as a nonpolar molecule due to its symmetrical appearance, but the unequal sharing of electrons between oxygen and hydrogen atoms results in a polar distribution of charge.