Do related molecules with the same number of electrons occupy the same amount of space, or are other factors (beyond electron count) of importance when dictating overall size requirements? Obtain equilibrium geometries for methyl anion, ammonia, and hydronium cation using the HF/6-31G* model and compare electron density surfaces corresponding to enclosure of 99% of the total electron density. Do the three molecules take up the same amount of space? If not, why not?