Chapter 7 Chemical Formulas and Chemical Compounds

7.1 Chemical Names and Formulas  naming simple ions cations – use the name of the metal  Na + = sodium ion  Ca 2+ = calcium ion  Al 3+ = aluminum ion multivalent cations  transition metals and group 13, 14, 15 metals  assign a roman numeral that equals charge  Fe 2+ = Iron(II)  Fe 3+ = Iron(III) see list of multivalent metals

 anions use element name drop ending/root remains add – ide  O 2- = oxygen = oxide  Cl - = chlorine = chloride  C 4- = carbon = carbide  S 2- = ??  Br - = ??  Sn 4+ = ??  Mn 3+ = ?? sulfide bromide tin (IV) manganese (III)

 polyatomic ions many atomed ions a group of atoms that behave as a single particle with a single charge SO 4 2- = sulfate can replace any 2- ion(like sulfide, oxide,…)

 polyatomic anion names no discernible pattern with oxygen, subscript or charge hint – memorize all –ate ion names  such as sulfate = SO 4 2-  then sulfite = SO 3 2-  chlorate = ClO 3 -, chlorite =  phosphate = PO 4 3-, phosphite = hypo – prefix used to indicate 2 less oxygen than –ate ion  SO 2 2- = hyposulfite per – prefix used to indicate 1 more oxygen than –ate ion  SO 5 2- = persulfate

 writing ionic formulas 1.write symbol and charge of cation 2.write symbol and charge of anion 3.if oxidation = reduction – formula complete calcium oxide Ca 2+ O 2- 4.if oxidation ≠ reduction – criss-cross number aluminum fluoride Al 3+ F -  Al 3+ F - iron(III) sulfide Fe 3+ S 2-   AlF 3 Fe 2 S 3

Naming Binary Molecules 1)determine how many of 1 st element use prefix to tell how many, if more than 1 1=mono-6=hexa- 2=di-7=hepta- 3=tri-8=octa- 4=tetra-9=nona- 5=penta-10=deca- 2)name element 3)determine how many of 2 nd element use prefix to tell how many 4)use root of 2 nd element 5)end with -ide

name the following: CO 2 = P 2 O 5 = N 3 Cl 7 = CaSO 4 = write fomulas for the following: carbon tetrachloride = carbon monoxide = disulfur hexafluoride = the general order: C, P, N, H, S, I, Br, Cl, O, F carbon dioxide diphosphorus pentoxide trinitrogen heptachloride calcium sulfate CCl 4 CO S2F6S2F6

7.3 Using Chemical Formulas formula mass the sum of the atomic masses of all atoms in a formula the molar mass of a compound empirical formula the smallest/simplest whole # ratio of atoms in a compound all ionic compounds