The sodium nucleus `""_(11)^(23)Na` contains

Options

A. 11 electrons
B. 12 protons
C. 23 protons
D. 12 neutrons

Explanation

To determine the contents of the sodium nucleus \( _{11}^{23}\text{Na} \), we need to analyze the information provided by the atomic number and mass number.

### Step-by-Step Solution:

1. **Identify the Atomic Number and Mass Number**:
- The atomic number (Z) of sodium \( _{11}^{23}\text{Na} \) is 11.
- The mass number (A) of sodium \( _{11}^{23}\text{Na} \) is 23.

2. **Determine the Number of Protons**:
- The atomic number (Z) represents the number of protons in the nucleus.
- Therefore, sodium has **11 protons**.

3. **Calculate the Number of Neutrons**:
- The number of neutrons (N) in the nucleus can be calculated using the formula:
\[ N = A - Z \]
- Substituting the values:
\[ N = 23 - 11 = 12 \]
- Thus, sodium has **12 neutrons**.

4. **Determine the Number of Electrons**:
- In a neutral atom, the number of electrons is equal to the number of protons.
- Therefore, sodium has **11 electrons**.

### Summary of Contents in Sodium Nucleus:
- **Protons**: 11
- **Neutrons**: 12
- **Electrons**: 11 (not part of the nucleus, but included for completeness)

### Conclusion:
The sodium nucleus \( _{11}^{23}\text{Na} \) contains **12 neutrons**. Thus, the correct answer is option D.