The number of neutrons in deuterium is

Options

A. 0
B. 1
C. 2
D. 3

Answer

To determine the number of neutrons in deuterium, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Element**: Deuterium is an isotope of hydrogen. The chemical symbol for deuterium is \( ^2_1H \).

2. **Understand Atomic Number and Mass**:
- The atomic number (Z) of hydrogen (and hence deuterium) is 1. This means that deuterium has 1 proton.
- The atomic mass (A) of deuterium is 2. This is the total number of protons and neutrons in the nucleus.

3. **Use the Formula**:
- The relationship between the atomic mass (A), atomic number (Z), and the number of neutrons (N) is given by the formula:
\[ A = Z + N \]
- Rearranging this formula to find the number of neutrons gives:
\[ N = A - Z \]

4. **Substitute the Values**:
- For deuterium:
- \( A = 2 \) (atomic mass)
- \( Z = 1 \) (atomic number)
- Plugging in the values:
\[ N = 2 - 1 = 1 \]

5. **Conclusion**: The number of neutrons in deuterium is 1.

### Final Answer:
The number of neutrons in deuterium is **1**.

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