Why does a sodium ion have a charge of 1 plus?

Answer 1

The obvious part of the answer is: "because it loses one electron". Why it loses an electron is what I will explain.

Solid sodium, properly protected from air and moist, or sodium dissolved in some solvents, appears in a neutral Na2 form, but sodium has a single electron in its valence orbital, and that tips the way it works. In water, the scenario changes. Liquid water has OH- and H30+ ions besides the common H2O molecule. H2O and H3O+ [I'm not sure these are both the right molecules] can create stronger bonds, with an electron, than sodium, because that electron will occupy a lower energy orbital; the lowest, actually, the one present in hydrogen. [I can't remember the formula for the reaction and it has been too long for me to know how to write it. Could someone do it?]

You might say that the electron is attracted to the positively charged ion or the polarized molecule, more than it is attracted to sodium, resulting in the loss of an electron from Na, and transforming it into Na+.

If an extremely thorough description is necessary, and ignoring the attraction idea, this is what someone would say to be (almost) absolutely detailed:

A physical system always tends towards the state of least energy and, the position of the electron, in the hydrogen atom, has lower energy than the one in the sodium atom. Bonds between electrons and nuclei are described by quantum physics. The electrons in an orbital are not "in" the orbital, they simply have a higher probability of Manifesting in that orbital: an orbital is a distribution of probabilities; it is nothing like an orbit. The presence of positive ions, or polarized molecules, increases the probability of an electron revealing itself closer to those structures; it reshapes the orbital. Even if this was not the case, there is always the probability that one of the valence electron manifests itself close enough to another molecule, to be captured by the nucleus of one of its atoms. Since that is the state of minimum energy, the electron will have higher probability of staying there. The transference of electrons in the other way also happens but, because the first is more probable than the second, the net result will be that, for all purposes, sodium appears as the Na- ion in water.

Answer 2

The sodium ion loss only one electron.