An element X has two isotopes, \(^{65}X_{30}\) and \(^{66}X_{30}\) with relative abundance of 60 % and 40% respectively. The relative atomic mass of X is
- 66.00
- 65.50
- 65.00
-
65.40
The correct answer is: D
Explanation
Isotope \(^{65}X_{30}\) (with a mass of 65 and an abundance of 60%):
Relative mass contribution = (65 * 60%) = 39.00
Isotope \(^{66}X_{30}\) (with a mass of 66 and an abundance of 40%):
Relative mass contribution = (66 * 40%) = 26.40
Now, add the relative mass contributions of both isotopes:
Relative atomic mass \(A_r\) = 39.00 + 26.40 = 65.40
So, the relative atomic mass of element X is 65.40. The correct option is:
65.40