Many metals have the ability to exist in multiple oxidation states, which means they can lose different numbers of electrons and form ions with varying charges. This property is particularly common among transition metals. Here are some notable examples:
- Iron (Fe): Iron can have a charge of +2 (ferrous) or +3 (ferric). The +2 state is seen in compounds like iron(II) sulfate, while the +3 state is common in iron(III) chloride.
- Copper (Cu): Copper primarily exhibits +1 (cuprous) and +2 (cupric) oxidation states. The +1 state is found in copper(I) oxide, and the +2 state is seen in copper(II) sulfate.
- Lead (Pb): Lead can be found in +2 and +4 oxidation states. Lead(II) oxide is a common compound, as is lead(IV) oxide.
- Manganese (Mn): Manganese can have multiple oxidation states, typically +2, +4, +6, and +7, with potassium permanganate (KMnO₄) representing the +7 state.
- Chromium (Cr): Chromium can also exhibit multiple charges, commonly +2, +3, and +6. Chromium(VI) oxide (CrO₃) is a well-known example of its +6 oxidation state.
These metals are known as variable valency metals, and their ability to adopt multiple oxidation states makes them essential in various chemical reactions, industrial applications, and biological processes.