Xenon is already stable alone, because it has a complete octet, or 8 electrons. This graph is not an ion because it shows xenon is its default state, consisting of 8 electrons.
It is not a molecule because a molecule is a group of atoms, or a compound, what is shown is a singular atom.
A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7.