Propose an equation for how the periodic table of elements Cl mass of 35.453 amu was reached?

Equation done below

Explanation:

Chlorine has two naturally occurring stable isotopes which are 35Cl (75.77%) and also 37Cl (24.23%).. However, the mass of the 35Cl isotope is 34.96885 amu while that of the 37Cl isotope is 36.96590 amu

Now, to calculate the relative atomic mass, we will do it as;

A_r = (Mass of 35Cl × fraction of 35 Cl) + (Mass of 37 Cl × fraction of 37Cl)

A_r = ((34.96885 × 75.77) + (36.96590 × 24.23))/100

A_r = 35.4527 ≈ 35.453 amu