The number of certain atoms coupled with or displaced with another atom to produce a compound is referred to as valency. Two hydrogen atoms interact with one oxygen atom to form water (H 2O). Because water requires two hydrogen atoms, oxygen has a valency of two.
In order to create the noble gas configuration, an atom must be able to receive or lose electrons. It refers to an element’s capacity to mix with other elements. It is calculated by counting the number of electrons in each atom’s outermost shell (also known as the valence shell).