Mono+ Polyatomic Ionic Compounds Study Guide: Oxidation Numbers of Monatomic Ions
1+
cesium, Cs+
copper (I), Cu+
gold (I), Au+
hydrogen, H+
lithium, Li+
potassium, K+
silver, Ag+
sodium, Na+
2+
barium, Ba
beryllium, Be2+
cadmium, Cd2+
calcium, Ca2+
chromium (II), Cr2+
cobalt (II), Co2+
copper (II), Cu2+
iron (II), Fe2+
lead (II), Pb
magnesium, Mg2+
manganese (II), Mn2+
mercury (II), Hg2+
nickel (II), Ni2+
platinum (II), Pt2+
tin (II), Sn2+
zinc, Zn2+
3+
aluminum, Al3+
antimony (III), Sb3+
bismuth (III), Bi3+
boron, B3+
chromium (III), Cr3+
cobalt (III), Co3+
gold (III), Au3+
iron (III), Fe3
fluoride, Fiodide, I-
2oxide, O2sulfide, S2-
3nitride, N3phosphide, P3-
2+
2+
1bromide, Brchloride, Cl-
4+
lead (IV), Pb4+
platinum (IV), Pt4+
silicon, Si4+
tin (IV), Sn4+
titanium (IV), Ti4+
5+
niobium (V), Nb5+
vanadium (V), V5+
4carbide, C4-
Charges of Common Polyatomic Ions
1+
ammonium, NH4+
1acetate, CH3COOazide, N3bromate, BrO3chlorate, ClO3cyanide, CNformate, HCOObicarbonate, HCO3-
hydroxide, OHhypochlorite, ClOiodate, IO3nitrate, NO3nitrite, NO2perchlorate, ClO4periodate, IO4-
2carbonate, CO32chromate, CrO42dichromate, Cr2O72sulfate, SO42sulfite, SO32tetraborate, B4O72thiosulfate, S2O32-
3phosphate, PO43-
1.
Sn(SO4)2
Tin must have a Roman numeral, either (II) or (IV) and the
anion is sulfate with a 2- charge. Two sulfates give -4, so
tin (IV) with a +4 charge balances. Therefore, tin (IV) sulfate.
2.
Mg(HCO3)2 Magnesium is always 2+ with NO ROMAN NUMERAL. The anion is
bicarbonate. Therefore, just magnesium bicarbonate.
3.
Al(CN)3
Aluminum is always 3+ with NO ROMAN NUMERAL. The anion is
cyanide. Therefore, just aluminum cyanide.
4.
FeSO3
Iron must have a Roman numeral, either (II) or (III) and the
anion is sulfite with a 2- charge. One sulfite gives -2, so
iron (II) with a +2 charge balances. Therefore, iron (II) sulfite.
5.
CoCl2
Cobalt must have a Roman numeral, either (II) or (III) and the
anion is chloride with a 1- charge. Two chlorides give -2, so
cobalt (II) with a +2 charge balances. Therefore, cobalt (II) chloride.
6.
Ag3P
Silver is always 1+ with NO ROMAN NUMERAL. The anion is
phosphide. Therefore, just silver phosphide.
7.
Ti3(PO4)4
Titanium must have a Roman numeral, (IV), and the anion is phosphate
with a 3- charge. Four phosphates give -12, so three titanium (IV)’s will
provide charge balance (3 X 4+). Therefore, titanium (IV) phosphate.
8.
CuOH
Copper must have a Roman numeral, either (I) or (II) and the
anion is hydroxide with a 1- charge. Thus, copper (I) hydroxide.
Oxidation Numbers of Monatomic Ions
1+
cesium, Cs+
copper (I), Cu+
gold (I), Au+
hydrogen, H+
lithium, Li+
potassium, K+
silver, Ag+
sodium, Na+
2+
barium, Ba2+
beryllium, Be2+
cadmium, Cd2+
calcium, Ca2+
chromium (II), Cr2+
cobalt (II), Co2+
copper (II), Cu2+
iron (II), Fe2+
1-
-
bromide, Br
chloride, Cl-
fluoride, F
iodide, I-
-
lead (II), Pb2+
magnesium, Mg2+
manganese (II), Mn2+
mercury (II), Hg2+
nickel (II), Ni2+
platinum (II), Pt2+
tin (II), Sn2+
zinc, Zn2+
3+
aluminum, Al3+
antimony (III), Sb3+
bismuth (III), Bi3+
boron, B3+
chromium (III), Cr3+
cobalt (III), Co3+
gold (III), Au3+
iron (III), Fe3
2-
3-
2-
3-
oxide, O
sulfide, S2-
nitride, N
phosphide, P3-
4+
lead (IV), Pb4+
platinum (IV), Pt4+
silicon, Si4+
tin (IV), Sn4+
titanium (IV), Ti4+
5+
niobium (V), Nb5+
vanadium (V), V5+
4carbide, C4-
Charges of Common Polyatomic Ions
1+
ammonium, NH4+
1-
acetate, CH3COO
azide, N3bromate, BrO3chlorate, ClO3cyanide, CNformate, HCOObicarbonate, HCO3-
-
hydroxide, OH
hypochlorite, ClOiodate, IO3nitrate, NO3nitrite, NO2perchlorate, ClO4periodate, IO4-
2carbonate, CO32chromate, CrO42dichromate, Cr2O72sulfate, SO42sulfite, SO32tetraborate, B4O72thiosulfate, S2O32-
3phosphate, PO43-
9.
manganese (II) phosphate
manganese (II) is Mn2+ and phosphate is PO43-.
Use the crisscross rule and parentheses for multiple
phosphates to give Mn3(PO4)2
10.
zinc carbonate
zinc is Zn2+ and carbonate is CO32-. There is no need
for the crisscross rule because the charges balance.
No need for parentheses either because there is
only one polyatomic carbonate ion. Thus, ZnCO3
11.
ammonium sulfate
ammonium is NH4+ and sulfate is SO42-.
Use the crisscross rule. Use parentheses for
multiple ammonium ions but not for the single
polyatomic sulfate ion. Thus, (NH4)2SO4
12.
barium hydroxide
barium is Ba2+ and hydroxide is OH-.
Use the crisscross rule and parentheses for multiple
hydroxides to give Ba(OH)2
13.
lead (IV) tetraborate
lead (IV) is Pb4+ and tetraborate is B4O72-.
If you use the crisscross rule and parentheses for
multiple tetraborates you get, Pb2(B4O7)4 which is
WRONG! You must reduce it to a simpler form which
is Pb(B4O7)2 This is like changing Pb2O4 to PbO2.
14.
ammonium azide
ammonium is NH4+ and azide is N3-. There is no need
for the crisscross rule or parenthesis. Thus, NH4N3