The atomic weight of an unknown element, in atomic mass units (amu), is approximately 20% less than that of calcium. The atomic weight of calcium is 40 amu. Which of the following best approximates the atomic weight, in amu, of the unknown element?

Options

A. 8
B. 20
C. 32
D. 48

Explanation

To find the atomic weight of the unknown element, we follow these steps:

1. **Identify the atomic weight of calcium**: The atomic weight of calcium is given as 40 amu.

2. **Calculate 20% of calcium's atomic weight**:
\[ 20\% \text{ of } 40 \text{ amu} = \frac{20}{100} \times 40 = 8 \text{ amu} \]
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