Rules for Naming Ions Negative ions--Anions 1.The names of the monatomic anions are formed by replacing the end of the names of elements by-ide H H-hydrogen H:hydride ion O-oxygen O2-:oxide ion,:peroxide ion, S2- S-sulfur S-:sulfide ion N3- N-nitrogen N:nitride ion F F-fluorine F:fluoride ion Cl-chlorine Cl:chloride ion Br Br-bromine Br:bromide ion I I-iodine I:iodide ion 2.Afew simple polyatomic ions also have names ending in -ide OH:hydroxide ion; CN-:cyanide ionH hydrogen O oxygen S sulfur N nitrogen     1. The names of the monatomic anions are formed by replacing the end of the names of elements by –ide F fluorine Cl chlorine Br bromine I iodine     2 2 3 H O S N     2 2- 2 2 3 : : ; O : ; : : H hydr ion O ox ion perox ide ion S sulf i ide ide on N nitr ide ide ion     F Cl Br I     : : : : F fluor ion Cl chlor ion Br brom ion ide ide i I iod de ide ion     2. A few simple polyatomic ions also have names ending in –ide OH : hydroxide ion; CN : cyanide ion  