Simple Chemical Nomenclature 3 classes of simple compounds…naming convention depends on type. Ionic Compounds – look for the following at the beginning of the formula: metals or polyatomic cations (NH4+, etc) Molecular Compounds – look for the presence of nonmetals only, but be on alert for polyatomic ions with only nonmetals (NH4+, etc) Acids – these will contain a hydrogen atom (H) where the cation should be and will exist in aqueous solution. Some organic acids are called “acid” even when pure, but this is just a simple way to name them…they will have a much more complicated IUPAC name as well

1. Ionic Nomenclature CATIONS (+ ions) ANIONS ( ions) Representative metals (1A-3A) maintain their names as listed on the periodic table Transition metals (d and f blocks) most will have multiple charges and these will be indicated in parentheses by roman numerals Zn and Cd – exceptions to the rule for d- block, always +2, charge not needed in compound name Ag – while multiple charges are known, nearly always +1, charge not needed in compound name Pb and Sn – are representative, but can be either +2 or +4, charge needed in name Polyatomic Ions – keep their name Representative elements (6A-8A) keep the root but add ide as a suffix Polyatomic ions – keep their name

Ionic Examples- whiteboards Example 1  Give the names of the following compounds: Li2S , LiClO3 , CrCl6 , Pb(OH)2 Example 2 – Write formulas for the following compounds: aluminum oxide, sodium sulfite, nickel(III) iodide, tin(IV) phosphate

Ionic Examples- whiteboards Example 1  Give the names of the following compounds: Li2S , LiClO3 , CrCl6 , Pb(OH)2 Lithium sulfide Lithium chlorate Chromium (VI) chloride Lead (II) hydroxide Example 2 – Write formulas for the following compounds: aluminum oxide, sodium sulfite, nickel(III) iodide, tin(IV) phosphate

2. Covalent Nomenclature Simple covalent nomenclature uses prefixes to indicate the number of each atom present. The least electronegative (more metallic) atom comes first, followed by the more electronegative atom The prefix “mono” can be omitted on the first element Odd vowel combinations such as “ao” can often be shortened 1 – mono 2 – di 3 – tri 4 – tetra 5 – penta 6 – hexa 7 – hepta 8 – octa 9 – nona 10 – deca

Covalent Examples- whiteboards Example 1 – give the names of the following compounds: S2Cl2 , N2S5 , NO2 , N2O5 Example 2 – write formulas for the following compounds: trisulfur dioxide, diselinium monochloride, tetraphosphorus pentoxide

Covalent Examples- whiteboards Example 1 – give the names of the following compounds: S2Cl2 , N2S5 , NO2 , N2O5 Disulfur dichloride Dinitrogen pentasulfide Nitrogen dioxide Dinitrogen pentoxide Example 2 – write formulas for the following compounds: trisulfur dioxide, diselinium monochloride, tetraphosphorus pentoxide

Acid Nomenclature

Acid Examples- whiteboards Example 1 – give the names of the following compounds: HBr , H2CrO4 , HCN , HNO2 Example 2 – write formulas for the following compounds: oxalic acid, sulfurous acid, hydrophosphoric acid

Acid Examples- whiteboards Example 1 – give the names of the following compounds: HBr , H2CrO4 , HCN , HNO2 Hydrobromic acid Chromic acid Hydrocyanic acid Nitrous acid Example 2 – write formulas for the following compounds: oxalic acid, sulfurous acid, hydrophosphoric acid