Ch. 9: Chemical Nomenclature Names and Formulas

Review… Ionic Charges

Review… Ions Cation: + charged ion ex: Na (sodium) Na + (sodium ion) Anion: - charged ion ex: Br (Bromine) Br - (Bromine ion) Polyatomic Ion: a tightly bound group of atoms that form a molecule and have a + or – charge ex: NO 3 - (nitrate ion)

Ionic Formulas + charge of a cation must balance with the - charge of an anion So, net ionic charge of a formula = 0 Number of atoms are determined by the charge of each cation and anion ex: Ca 2+ + Cl -  CaCl 2 (2+) + 2(1-) = 0 I.

Ionic Formulas Binary compound: made of 2 elements Ternary compound: made of 3 elements ex: H + + (NO 3 ) -  H(NO 3 ) Ternary compound

Polyatomic Ion Formulas An ion formed from one atom is a monatomic ion An ion formed from a compound (2 or more atoms) is a polyatomic ion ex: Na + monatomic ion NH 4 + polyatomic ion

Naming Ionic Compounds Binary Ionic Compounds consist of a METAL and a NON-METAL The name of the metal (cation) is first The name of the non-metal (anion) has the suffix -ide added ex: NaCl is Sodium Chloride Overall charge must equal zero. –If charges cancel, just write symbols. –If not, use subscripts to balance charges. II.

Names of Common Ions Anions are named by adding the suffix -ide to the stem of the name of the nonmetal

Naming Transition Metals Transition metals can form more than one cation (they are essentially metals, so have tendency to lose valence electrons) To distinguish between them, the number of excess charges is written in roman numerals following the name of the metal, then by the word "ion". For example: Fe 2+ iron (II) ion Fe 3+ iron (III) ion

Naming Polyatomic Ions There is no specific naming rule except that: Polyatomic cations are followed by “ion” Polyatomic anions add the suffix –ide to the end element (if they don’t contain an oxygen atom in the molecule) ex: (cation) NH 4 + ammonium ion (anion) CN - cyanide HS - hydrogen sulfide III.

Polyatomic Ion Names When two or more polyatomic ions consist of the same ions those containing more oxygen atoms end with the suffix "ate" those with the fewer oxygen atoms end with the suffix "ite". ex: SO 4 2- Sulfate SO 3 2- Sulfite NO 3 - Nitrate NO 2 - Nitrite

Naming Molecular Compounds Molecular compounds = Covalent bonds NON- METALSMolecules generally consist of 2 NON- METALS Molecular name starts with the element on the left side of the Periodic Table The second element has the suffix –ide IV. ex: CO 2 carbon dioxide

Naming Molecular Compounds cont’d. Number of Atoms Prefix 1Mono- 2Di- 3Tri- 4Tetra- 5Penta- 6Hexa- 7Hepta- 8Octa- 9Nona- 10Deca- Greek prefixes are used for number of atoms ex: CO carbon monoxide CO 2 carbon dioxide N 2 O 5 dinitrogen pentaoxide

Learning Check 1. aluminum oxide a) Al 2 O 3 b) AlO 3 c) Al 3 O 3 2. Potassium nitride a) KN 3 b) K 2 N 3 c) K 3 N 3. Dihydrogen monoxide a) H 2 O b) OHc) HO 2 4. Tin(IV) nitrate a) Sn(NO 3 ) 4 b) Sn(NO 3 ) 2 c) Sn 4 (NO 3 )

Learning Check Ionic Compounds: CaCl 2___________________ Al 2 O 3 ___________________ Pb 2+ I ___________________ Polyatomic Ions: H2SH2S ___________________ CrO 4 2- ___________________ SO 4 2- ___________________ Ca 2+ (NO 2 - ) 2 ___________________ Molecular Compounds: CCl 4 ___________________ N2ON2O