The number of neutrons in an atom of Na is

Options

A. 23
B. 11
C. 34
D. 12

Explanation

To find the number of neutrons in an atom of sodium (Na), we can follow these steps:

### Step 1: Identify the Atomic Number and Mass Number
- The atomic number (Z) of sodium (Na) is 11. This number represents the number of protons in the atom.
- The mass number (A) of sodium is 23. This number represents the total number of protons and neutrons in the atom.

### Step 2: Use the Formula to Calculate Neutrons
- The number of neutrons can be calculated using the formula:
\[ \text{Number of Neutrons} = \text{Mass Number} - \text{Atomic Number} \]
- In this case, we substitute the values:
\[ \text{Number of Neutrons} = 23 - 11 \]

### Step 3: Perform the Calculation
- Now, we perform the subtraction:
\[ 23 - 11 = 12 \]

### Conclusion
- Therefore, the number of neutrons in an atom of sodium (Na) is **12**.

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