Naming Compounds & Writing Formulas

Binary compounds with standard group charges Format: Metal Non-metal i.e. NaCl, Al 2 O 3 Subscript tells number of atoms in molecule – Ones are not written CationAnion Periodic Table Location MetalNon-metal ChargePositiveNegative Name changeNone (stays the same) Ending changes to -ide

Criss-cross Aluminum & oxygen Al +3 O -2 Aluminum oxide Cross with number not sign 23 -> Al 2 O 3

Criss-cross Calcium & fluorine Ca +2 F -(1) Aluminum oxide 1 2 -> Ca 1 F 2 -> CaF 2 (don’t write 1’s)

Criss-cross Potassium & oxygen K +(1) O -2 Potassium oxide 2 1 -> K 2 O 1 -> K 2 O

Criss-cross Aluminum & nitrogen Al +3 N -3 Aluminum nitride 3 3 -> Al 3 N 3 -> AlN (lowest ratio)

Cations with more than 1 charge Compounds including cations with more than 1 possible charge (cation name followed by Roman numeral) – Roman numeral tells oxidation number/cation charge – Compound will have 2 names – stock name & classical name – Look at chart for classical name Roman Numerals 1I 2II 3III 4IV

Criss-cross Chromium (III) & oxygen Cr +3 O -2 Chromium (III) oxide Chromic oxide 2 3 -> Cr 2 O 3

Criss-cross Lead (IV) & nitrogen Pb +4 N -3 Lead (IV) nitride Plumbic nitride 3 4 -> Pb 3 N 4

Criss-cross Manganese (III) & phosphorus Mn +3 P -3 Manganese (III) & phosphide Manganic & phosphide 3 3 -> Mn 3 P 3 -> MnP (lowest ratio)

Criss-cross Lead (IV) & sulfide Pb +4 S -2 Lead (IV) sulfide Plumbic sulfide 2 4 -> Pb 2 S 4 -> PbS 2 (lowest ratio)

Polyatomic ions Many atom ions (poly = many) Endings – -ate, -ite – ide (hydroxide, cyanide) <- most likely to cause problems – ium (ammonium, cation) DO NOT CHANGE ENDINGS

Criss-cross Aluminum & sulfate Al +3 SO 4 -2 Aluminum sulfate 23 -> Al 2 (SO 4 ) 3

Criss-cross Calcium & phosphate Ca +2 PO 4 -3 Calcium phosphate 22 -> Ca 3 (PO 4 ) 2

Criss-cross Calcium & sulfite Ca +2 SO -2 Calcium sulfite 23 -> Ca 2 (SO 3 ) 2 -> CaSO 3 (lowest ratio)

Criss-cross Aluminum & phosphate Al +3 PO 4 -3 Aluminum phosphate 33 -> Al 3 (PO 4 ) 3 -> AlPO 4 (lowest ratio)

Criss-cross Lead (IV) & oxalate Pb +4 C 2 O 4 -2 Lead (IV) oxalate Plumbic oxalate 2 4 -> Pb 2 (C 2 O 4 ) 4 -> Pb(C 2 O 4 ) 2 (lowest ratio)