Question

Antimony has two stable isotopes. Given that 43.8% of natural antimony has a mass of 122.904 amu, and the other stable isotope has a mass of 120.868 amu, what is the average atomic mass of antimony?**

A) \(120.384 \, \text{amu}\)

B) \(121.181 \, \text{amu}\)

C) \(122.395 \, \text{amu}\)

D) \(123.136 \, \text{amu}\)

Answer 1

To calculate the average atomic mass of antimony, we use the percentages of each isotope and their respective masses. The average atomic mass of antimony is 120.384 amu.

Step-by-step explanation:

To calculate the average atomic mass of antimony, we use the percentages of each isotope and their respective masses. The average atomic mass is calculated as the weighted average of the isotopes' masses. In this case, 43.8% of antimony has a mass of 122.904 amu, and the remaining percentage is the other stable isotope with a mass of 120.868 amu.

To calculate the average atomic mass, we can use the formula:

(% abundance of isotope 1 x mass of isotope 1) + (% abundance of isotope 2 x mass of isotope 2)

Using the given information, the calculation is: (0.438 x 122.904 amu) + (0.562 x 120.868 amu) = 120.384 amu.

Therefore, the average atomic mass of antimony is 120.384 amu.