Boron has two stable isotopes, `""^(10)B(19%)` and `""^(11)B(81%)`. The atomic mass that should appear for boron in the periodic table is

Options

A. `10.8`
B. `10.2`
C. `11.2`
D. `10.0`

Explanation

To find the atomic mass of boron that should appear in the periodic table, we will calculate the weighted average of its isotopes based on their relative abundances. Here are the steps to solve the problem:

### Step-by-Step Solution:

1. **Identify the isotopes and their atomic masses**:
- The two stable isotopes of boron are:
- \( ^{10}B \) with an atomic mass of 10 amu and an abundance of 19%.
- \( ^{11}B \) with an atomic mass of 11 amu and an abundance of 81%.

2. **Convert the percentages to decimal form**:
- For \( ^{10}B \): \( 19\% = 0.19 \)
- For \( ^{11}B \): \( 81\% = 0.81 \)

3. **Calculate the contribution of each isotope to the average atomic mass**:
- Contribution from \( ^{10}B \):
\[ 10 \, \text{amu} \times 0.19 = 1.9 \, \text{amu} \]
- Contribution from \( ^{11}B \):
\[ 11 \, \text{amu} \times 0.81 = 8.91 \, \text{amu} \]

4. **Sum the contributions**:
- Total contribution to the average atomic mass:
\[ 1.9 \, \text{amu} + 8.91 \, \text{amu} = 10.81 \, \text{amu} \]

5. **Conclusion**:
- The average atomic mass of boron that should appear in the periodic table is approximately \( 10.81 \, \text{g/mol} \).

### Final Answer:
The atomic mass of boron in the periodic table is approximately **10.81 g/mol**.

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