Both oxygen and nitrogen are sp3 hybridized with lone pairs occupying hybrid orbitals.
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In water and ammonia the central oxygen and nitrogen atoms are sp3 hybridized, so their four electron domains point toward the corners of a tetrahedron. In water two hybrid orbitals hold bonding pairs and two hold lone pairs, while in ammonia three hybrids form bonds and one holds the lone pair. Experimental bond angles are smaller than 109.5 degrees, which is attributed to stronger repulsion from lone pairs and to greater p character in the bonding orbitals. This explanation reconciles observed geometries with a simple hybridization picture. It is a standard example of applying sp3 hybridization to heteroatoms.
Key ideas: Compare angles to see the effect of lone pair: CH4 109.5, NH3 107, H2O 104.5. Real hybrid orbitals are not exactly equal: bond pairs have more p character, lone pairs have more s. For H2O the O-H bonds use about 80 percent p character, giving a smaller angle. The lone pairs also explain basicity, hydrogen bonding and the donor sites of water.
Common mistakes and connections: Students often claim that both molecules have equal sp3 orbitals and exactly 109.5 degrees, or that lone pairs are in pure p orbitals. Photoelectron spectra show two different lone pair energies in water, which is hard to reconcile with two equal sp3 lone pairs. Links to Bent's rule, VSEPR and hydrogen bonding.
Nitrogen in ammonia is sp3 hybridized, with three hybrids bonding to hydrogen and one holding the lone pair, giving about 107 degrees. The interactive lesson shows this as a live animation or chart.
Both oxygen in water and nitrogen in ammonia are sp3 hybridized, with two and one hybrid orbitals respectively holding lone pairs.
Both oxygen and nitrogen are sp3 hybridized with lone pairs occupying hybrid orbitals.
Hybridization of Water and Ammonia is a intermediate topic in Bonding & Molecular Structure. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Bonding & Molecular Structure first: sp2 Hybridization, sp Hybridization, sp3d and sp3d2 Hybridization.
The next topics in Bonding & Molecular Structure are Molecular Orbital Theory and Bonding Molecular Orbital.
Yes. The interactive lesson includes a self-check question on Hybridization of Water and Ammonia, and the Bonding & Molecular Structure quiz draws on every topic in this area.
Hybridization of Water and Ammonia is topic 58 of 104 in Bonding & Molecular Structure.