Question

there are 5 naturally occurring isotopes of the element zinc. the relative abundance and mass of each are as follow
64
30zn=48.89% 63.929 amu

66
30zn=27.81% 65.926

67
30zn=4.11% 66.927

68
30zn = 18.57% 67.925

70
30zn = 0.62% 69.925

find the average atomic mass of zinc

is it 0.4889(63.929)+0.2781(65.926) ....and then divide by 5 or 1?i am not sure .

14 years ago