Valence Shell Electron Pair Repulsion Theory, or VSEPR (pronounced "Vesper") predicts the molecular geometry of individual molecules. All the bonds to the central atom, plus all the lone pairs, equals the molecule's steric number. VSEPR Practice Molecules and Ions Here are forty-six molecules and ions that exhibit almost all the possibilities of molecular geometry. They are listed in order of numbers of electron domains - "regions of high electron density" - around the central atom(s). There are several molecules of each basic geometry. Jan 22, 2018 · It has five valence electrons. The hydrogen falls under the category one, and so we can say that it has only one valence electron. As we have three hydrogens in NH3, this valence electron should be multiplied by three. So, we have to add these electrons of nitrogen and hydrogen to get the total number of atoms.