We have that
The average atomic mass round and to the second decimal place (0.01) is
A_m=126.90
From the question we are told
Find the average atomic mass round and to the second decimal place (0.01)
80% 127I, 17% 126I, 3% 128I
Generally the equation for the Average Mass is mathematically given as
Where
a1 = 127
b1 = 80%
a2 = 126
b2 = 17%
a3 = 128
b3 = 3%
Therefore
In conclusion
The average atomic mass round and to the second decimal place (0.01) is
A_m=126.90
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