| Tetrahedral Electron Pair Geometry
In methane, ammonia, water and hydrogen fluoride, the electron
pair geometry is tetrahedral. All have four pairs of electrons
about the central atom (C, N, O, or F). See graphic on middle
In methane, C has four bonds.
In ammonia, N has 3 bonds and one lone pair of electrons.
In water, O has 2 bonds and 2 lone pairs of electrons.
In hydrogen fluoride, F as 1 bond and 3 lone pairs.