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The naming rules for monatomic cations are simple: the name of the ion is the same as the name of the metal.

Na+ is sodium ion.
If there is more than one possible cation, add a roman numeral with the charge of the ion to the end of the name. For example,
Fe+2 is iron(II)
Fe+3 is iron(III)

Monoatomic anions add the suffix ide to the stem of the name of the atom.

N-3: nitride
O-2; oxide
Cl-: chloride

Polyatomic ions have their own set of naming rules.

Example: What is the name of the S-2 ion?

Solution: This is an anion of sulfur, so we attach the -ide suffix to the root of sulfur. Drop the -ur, add -ide, and we have the sulfide ion


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