Valency
- The valency of an element is a measure of its combining power, i.e., the number of electrons that an atom of that element can gain, lose, or share in order to form chemical bonds with other atoms.
- For example, chlorine has a valency of 1 because it can gain one electron to form a stable chloride ion (Cl-).
- Valency is a positive integer that is equal to the number of valence electrons in an atom.
Oxidation State
- The oxidation state of an atom is a measure of the degree of oxidation or reduction of that atom in a compound.
- It is the net charge that an atom would have if all of its electrons were assigned to the atom that it is bonded to.
- For example, in water (H2O), the oxidation state of hydrogen is +1, and the oxidation state of oxygen is -2.
- Oxidation states can be positive, negative, or zero.
In general, the valency of an element is the same as its oxidation state in its most common compounds. However, there are some exceptions to this rule, such as transition metals.
Transition metals can have multiple oxidation states, depending on the compound that they are in. For example, iron can have an oxidation state of +2 or +3.
The valency of an element is a useful concept for understanding how atoms form chemical bonds. The oxidation state of an element is a useful concept for understanding the chemical reactions that an element can undergo.
