Question

Two isotopes of nickel have a percent abundance of 0.93% and 68.08% with masses of 63.93

amu and 57.93 amu respectively. What is the atomic mass of these two isotopes? Explain why
the average mass is closer to actual amu of 58.69 for nickel.

Answer 1

Answer: The atomic mass of these two isotopes is 40.03 amu. The average mass is closer to actual amu of 58.69 for nickel as its percentage abundance is more.

Step-by-step explanation:

Mass of isotope 1 = 63.93

% abundance of isotope 1 = 0.93% =
`(0.93)/(100)`

Mass of isotope 2 = 57.93

% abundance of isotope 2 = (68.08)% =
`(68.08)/(100)`

Formula used for average atomic mass of an element :

`\text{ Average atomic mass of an element}=\sum(\text{atomic mass of an isotopes}* {{\text { fractional abundance}})`

`A=\sum[(63.93)* (0.93)/(100))+(57.93)* (68.08)/(100)]]`

`A= 40.03amu`

Therefore, the average atomic mass of nickel is, 40.03 amu. The average mass is closer to actual amu of 58.69 for nickel as its percentage abundance is more.