When dissolved in water sodium hydroxide almost completely dissociates into what ions?

Iodine (I2) is an example of a non-electrolyte. This is a purple-black solid at room temperature. When heated, it turns to a gas (sublimation) producing a beautiful violet cloud. It dissolves readily in many organic solvents, producing violet solutions in most cases and yellow-brown solutions in alcohols. Iodine is not very soluble in water, but produces a slightly yellow solution. No ions are produced when iodine dissolves in any of these solvents.

NaOH dissociates into Na+ and OH- ions which results in no change
As, water also contains OH- ions as the only negative ions

You use the atomic number to find out how many protons and neutrons there are in the atom. you use the atomic mass to find out how many protons and electrons there are in the atom.