Video narration
Why isn’t a water molecule straight? VSEPR theory says electron pairs around a central atom repel each other and spread out. In H2O, oxygen is the center and it has four electron pairs: two bonding pairs forming O–H bonds, and two lone pairs. If you look at electron domains, four pairs arrange as a tetrahedron to maximize distance. But the molecular shape counts only the atoms, not the lone pairs. The two lone pairs push a bit harder than bonding pairs, squeezing the H–O–H angle smaller. So instead of a straight line, the two hydrogens end up in a bent, or V-shaped, geometry. Electron-domain shape: tetrahedral. Molecular shape: bent.