What is the VESPER treatment of ammonia gas?
The ammonia molecule has FOUR regions of electron density around the central nitrogen atom..............and this leads to
Nitrogen has 5 valence electrons; hydrogen has 1 valence electron. And thus we have
Six of these electrons constitute the individual
And thus there are 4 orbitals, each containing 2 electrons, around the central nitrogen atom. The most stable geometric arrangement for these 4 orbitals, which MINIMIZES electrostatic interaction between LIKE electronic charges, is as a TETRAHEDRON, i.e.
But we describe molecular geometry on the basis of the disposition of ATOMS not lone pairs of electrons. And thus we describe the geometry of ammonia as
On the other hand we know that ammonia is a BASIC molecule, and it undergoes the base association reaction:
In ammonium ion, ALL the hydrogens are equivalent, and the molecule assumes a highly symmetrical tetrahedral shape. Thus
And if you can explain the geometry of ammonia, you can also easily account for the geometry of phosphine, methane, and water.......Try it out............