Question

Atomic mass practice and mass number review.
The average atomic mass of oxygen is 15.999 amu. Oxygen's isotopes are oxygen-16 , oxygen 17 and oxygen 18.
2. The average atomic mass of sliver is 107.8682 amy. Slivers isotopes are sliver 107 and sliver 109 .
3. The average atomic mass of iron is 55.845 amu. Iron's isotopes are iron54 , iron 56, iron 57, and iron 58.
Which isotope is most abundant? ____
What is the mass number of that isotope? __

Answer 1

To determine the most abundant isotope for each element based on the average atomic mass, we can analyze the given average atomic masses in relation to the isotopes.

1. **Oxygen**
- Average Atomic Mass: 15.999 amu
- Isotopes: Oxygen-16, Oxygen-17, Oxygen-18
- The average atomic mass is closest to 16 amu, suggesting that **Oxygen-16** is the most abundant isotope.
- **Mass Number of Most Abundant Isotope**: 16

2. **Silver**
- Average Atomic Mass: 107.8682 amu
- Isotopes: Silver-107, Silver-109
- The average atomic mass is closest to 108 amu, indicating that **Silver-107** is the most abundant isotope.
- **Mass Number of Most Abundant Isotope**: 107

3. **Iron**
- Average Atomic Mass: 55.845 amu
- Isotopes: Iron-54, Iron-56, Iron-57, Iron-58
- The average atomic mass is closest to 56 amu, suggesting that **Iron-56** is the most abundant isotope.
- **Mass Number of Most Abundant Isotope**: 56

To summarize:

- **For Oxygen**: Most Abundant Isotope: Oxygen-16, Mass Number: 16
- **For Silver**: Most Abundant Isotope: Silver-107, Mass Number: 107
- **For Iron**: Most Abundant Isotope: Iron-56, Mass Number: 56