Write the formulaMetal (cation)first(roman) indicates metal chargeAnion next, use first on PT for “ides” use half sheet for polyatomicsCation charge becomes anion subscript and vice versa(“criss-cross” charges)Reduce as necessary by greatest common factor

Sodium Chloride

Na+ Cl-NaCl

Magnesium fluoride

Mg2+ F-

MgF2

calcium hydroxide

Ca2+ OH-

Ca(OH)2

Name a formulaMetal (cation)first, just the name

no prefix, no suffixIFF!!! PT shows more than one charge for the metal, Use (roman) to indicate metal chargeCation charge = (anion charge)X(anion subscript)/(cation subscript) Anion name next

Fe3(PO4)2

Iron Iron ( )Iron ( ) Phosphate (3)x(2)/3=2Iron (II) Phosphate

+2+3

FeThere’s two oxidation states, so we’ll need roman numerals.

Anion charge is 3-Anion subscript is 2

Cation subscript is 3

Roman = 2

Parenthesis

• Use around polyatomics when there’s more than one in the molecule!