9.4: Chemical Monitoring and Management
Cations
Cations are a positively charged ion which means they have lost one or more electrons. Cations are formed from the elements in Groups 1, 2, 3 of the Periodic Table and from a number of the transition metals. See the Periodic Table for the locations of these Groups. Some common cations include:
The table below shows a number of common cations. The small number next to the plus sign indicates the number of electrons the atom has lost in order to become a cation. For example calcium which forms Ca2+ is in Group 2 of the Periodic Table loses 2 electrons and sodium which forms Na+ is in Group 1 of the Periodic Table loses 1 electron. Check out our interactive Periodic Table for where these cations are and find others.
Table 1: Common Cations
|
aluminium
|
Al3+
|
lead(IV)
|
Pb4+
|
|
ammonium
|
NH4+
|
lithium
|
Li+
|
|
barium
|
Ba2+
|
magnesium
|
Mg2+
|
|
calcium
|
Ca2+
|
manganese (II)
|
Mn2+
|
|
caesium
|
Cs+
|
mercury (I)
|
Hg22+
|
|
chromium (II)
|
Cr2+
|
mercury (II)
|
Hg2+
|
|
chromium (III)
|
Cr3+
|
nickel(II)
|
Ni2+
|
|
copper (I)
|
Cu+
|
potassium
|
K+
|
|
copper (II)
|
Cu2+
|
silver
|
Ag+
|
|
hydrogen
|
H+
|
sodium
|
Na+
|
|
iron (II)
|
Fe2+
|
tin (II)
|
Sn2+
|
|
iron (III)
|
Fe3+
|
tin (IV)
|
Sn4+
|
|
lead (II)
|
Pb2+
|
zinc
|
Zn2+
|
Australian Curriculum links
(ACSCH030) Ions are atoms or groups of atoms that are electrically charged due to an imbalance in the number of electrons and protons; ions are represented by formulae which include the number of constituent atoms and the charge of the ion (for example, O2–, SO42–)
(ACSCH031) The properties of ionic compounds (for example, high melting point, brittleness, ability to conduct electricity when liquid or in solution) are explained by modelling ionic bonding as ions arranged in a crystalline lattice structure with forces of attraction between oppositely charged ions
(ACSCH032) The characteristic properties of metals (for example, malleability, thermal conductivity, electrical conductivity) are explained by modelling metallic bonding as a regular arrangement of positive ions (cations) made stable by electrostatic forces of attraction between these ions and the electrons that are free to move within the structure