Positive ions

Negative Ions

Charges of positive ions

Almost all the common + ions are metallic.  The most notable exception is NH4+

The charges on metals in the representative groups can be determined from their position in the periodic table.  Most of the transtition metals have two or more commonly occuring charge.  In the following chart, the most commonly occuring charge for each element is listed first.

Group 1
All are 1+

Group 2
All are 2+

Group 3
Sc   3+ Y    3+ La     3+ Ac   3+

Group 4
Ti   4+   3+ Zr   4+ Hf     4+

Group 5
V   5+   4+ Nb   5+   3+ Ta   5+

Group 6
Cr   3+   2+ Mo   6+ W   6+

Group 7
Mn   2+   4+ Tc   7+ Re   7+

Group 8
Fe   3+   2+ Ru   3+   4+ Os   4+

Group 9
Co   2+   3+ Rh   3+ Ir   4+

Group 10
Ni   2+   3+ Pd   2+   4+ Pt   4+   2+

Group 11
Cu   2+   1+ Ag   1+ Au   3+   1+

Group 12
Zn   2+ Cd   2+ Hg   2+   1+

Group 13
Al   3+ Ga   3+ In   3+ Tl   1+   3+

Group 14
Ge   4+ Sn   4+   2+ Pb   2+   4+

Group 15
Sb   3+   5+ Bi   3+   5+

Group 16
Po   2+   4+

Charges of negative ions

The charges on the representative non-metallic elements can generally be determined from their position in the periodic table.  Except for hydroxide (OH-) any ion ending in –ide is an element from one of these groups, so you can locate it on the periodic table.

Group 15

 3-

Group 16

 2-

Group 17

 1-

Group 18

 No common ions

Most polyatomic ions are negative. Their names never end in –ide. The only common positive exceptions are NH4+, H3O+, and Mercury(I) Hg22+

1- ions
acetate CH3COO- hydrogen sulfite (bisulfite) HSO3-
benzoate C6H5COO- hydroxide OH-
chlorate ClO3- hypochlorite OCl-
chlorite ClO2- nitrate NO3-
cyanide CN- nitrite NO2-
dihydrogen phosphate H2PO4- perchlorate ClO3-
hydrogen carbonate (bicarbonate) HCO3- permanganate MnO4-
hydrogen sulfate (bisulfate) HSO4- thiocyanate SCN-
hydrogen sulfide (bisulfide) HS-

2- ions
carbonate CO32- silicate SiO32-
chromate CrO42- sulfate SO42-
dichromate Cr2O72- sulfite SO32-
hydrogen phosphate HPO42- thiosulfate S2O32-
oxalate C2O42-

3- ions
borate BO33- phosphate PO43-