The element chlorine has two naturally occurring isotopes. The isotopic masses and abundances of these isotopes are shown in the table.

Question

IsotopeIsotopic mass (u)Abundance (%)
Cl35	34.97	75.77
Cl37	36.97	24.23

Calculate the average atomic mass of chlorine to two digits after the decimal point.

average atomic mass:

Answer 1

(0.7577 x 34.97) + (0.2423 x 36.97) = 26.496769 + 8.957831 = 35.45 = average atomic mass for Cl