The mass (in gram) of one Mole of any material is called it's molar mass. It is equal to the 6.022×1023 atoms of that element or substance.
The number of particles (atoms, molecules or ions) present in one Mole of any substance is fixed,with a value of 6.022×1023. This number is called Avogadro Number or Avogadro constant.
This is represented by N0.
1 mole ( of anything) = 6.022×1023 in number.