Calculate the average atomic mass of chlorine if no distinction is made between its different isotopes?

Explanation

The element chlorine is mixture of 75.77 % of `.."_(17)^(37) Cl` and 24.23 % of `""_(17)^(37) Cl` . So the average atomic mass will be
`(75.77)/(100) xx 34.96885u + (24.23)/(100) xx 36.96593 u= 35.453u`
In fact , the chemist uses the averge atomic mass or simply called chemical atomic weight (35.453 u for chlorine) of an element . So it must be eremebered that the atomic mas whichs is mentioned in the periodic table is basically averaged atomic mass