Define Valency. Give Valency to Copper and Iron?

Valency is a term used in chemistry to describe the ability of an atom to bond with other atoms. It indicates the number of electrons an atom can lose, gain, or share to form a stable chemical bond. It is the measure of an atom’s combining power with other atoms when it forms chemical compounds or molecules.

For example, let’s look at the valencies of copper and iron:

1. Copper (Cu): Copper typically has a valency of +1 or +2. The most common valency of copper is +2, but in some compounds, like copper(I) oxide (Cu₂O), it shows a valency of +1.
2. Iron (Fe): Iron can have valencies of +2 or +3. When iron has a valency of +2, it forms iron(II) compounds, like iron(II) sulfate (FeSO₄). With a valency of +3, it forms iron(III) compounds, like iron(III) chloride (FeCl₃).

The valency of an element can vary depending on the compound it forms, reflecting the different ways an element can combine with others. This concept is fundamental in understanding how elements react and combine in chemistry.