Sodium ion
Charge: 1+ · Type: Cation · Molar mass: 22.990 g/mol
Made of: sodium
How it forms
A neutral sodium atom has one electron in its outer shell. Losing that electron gives the ion the stable electron arrangement of neon, which is why sodium almost always forms Na+ rather than any other charge. In water the ion is surrounded by a shell of water molecules.
Naming note
Cations keep the element's name, so Na+ is simply the sodium ion. In formulas it is written first, as in sodium chloride.
Examples in compounds
Sodium chloride
Sodium hydroxide
Sodium bicarbonate