wat is a valency,atomic mass no. &explain avagadro's no.
Valence, also known as valency or valence number, is a measure of the number of bonds formed by an atom of a given element.
Atomic Number:-The number of protons present in the nucleus is equal to atomic number (Z)
Mass Number: - The total number of protons (Z) and neutrons (n) is equal to mass number (A) of the atom.
Mass number (A) = Number of protons (Z) + Number of neutrons (n)
Avogadros number is equal to the number of particles or entities present in one mole of a substance.