Question

The element chlorine has two naturally occurring isotopes. About 75% of chlorine isotopes are Cl35 and about 25% are Cl37. What is the average atomic mass of chlorine atoms?
A. 35.45 amu
B. 36.45 amu
C. 37.45 amu
D. 38.45 amu

Answer 1

(75% of  35)  + (25% of 37)

0.75*35  + 0.25*37 = 35.5

35.50 amu