Atomic number is a fundamental property of an element and it is unique for each element. It is equal to the number of protons in the nucleus of an atom. The atomic number of an element is represented by the symbol "Z". For example, the atomic number of hydrogen is 1, the atomic number of helium is 2, and so on.
Molar mass, on the other hand, is the mass of one mole of a substance. One mole of a substance is defined as the amount of that substance that contains exactly 6.02214076 × 1023 representative particles of the substance (usually atoms, molecules, or ions). The molar mass of an element is the mass of one mole of atoms of that element and it is expressed in grams per mole (g/mol). The molar mass of an element is the sum of the atomic masses of all the atoms that make up one atom of that element.
For example, the molar mass of hydrogen is 1.008 g/mol, the molar mass of helium is 4.0026 g/mol, and so on. As you can see, the molar mass of an element is not equal to its atomic number.
