Solubility Rules
The following compounds are soluble:
1)
2)
3)
4)
All common group 1A and NH4+ compounds.
All common NO3- (nitrate), CH3COO- (acetate), ClO4- (perchlorate)
compounds.
All common Cl-, Br-, I- compounds, except those of Ag+, Pb2+, Cu+, and Hg22+
(mercurous).
All common SO42- (sulfate) compounds, except those of Ca2+, Sr2+, Ba2+, and
Pb2+.
The following compounds are insoluble:
1)
All common metal hydroxides, except those of group 1A and the larger
members of group 2A (starting with Ca2+).
2)
All common carbonates (CO32-) and phosphates (PO43-), except those of group
1A and NH4+.
3)
All common sulfides (S2-), except those of group 1A, group 2A, and NH4+.
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Rules for Assigning Oxidation Numbers
General rules:
1)
2)
3)
4)
All atoms in their elemental form have an O.N. of zero (i.e. Na, Cl2, and O2).
All monatomic ions have an O.N. equal to the ion charge (Na+ [O.N.=+1], O2[O.N.=-2]).
The sum of the oxidation numbers for atoms in a compound equals zero.
The sum of the oxidation numbers for atoms in a polyatomic ion equals the
charge on the polyatomic ion.
Specific rules:
1)
2)
3)
Group 1A:
Group 2A:
Hydrogen:
4)
5)
Fluorine:
Oxygen:
6)
Group 7A:
O.N. = +1 in all compounds.
O.N. = +2 in all compounds.
O.N. = +1 when combined with any nonmetal.
O.N. = -1 when combined with any metal and boron.
O.N. = -1 in all compounds.
O.N. = -1 in peroxides (i.e. H2O2, Na2O2).
O.N. = -2 in all other compounds.
O.N. = -1 when combined with any atom, except oxygen and a
halogen higher in the group.