The sum of the number of neutrons and protons in the three isotopes of hydrogen is :

Options

A. 6
B. 4
C. 3
D. 5

Explanation

To solve the question regarding the sum of the number of neutrons and protons in the three isotopes of hydrogen, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Isotopes of Hydrogen**:
The three isotopes of hydrogen are:
- Protium (¹H)
- Deuterium (²H)
- Tritium (³H)

2. **Determine the Atomic Number and Mass Number**:
- All isotopes of hydrogen have the same atomic number (Z = 1), which means they all have 1 proton.
- The mass numbers (A) for the isotopes are:
- Protium: A = 1
- Deuterium: A = 2
- Tritium: A = 3

3. **Calculate the Number of Neutrons**:
The number of neutrons (N) can be calculated using the formula:
\[ N = A - P \]
where P is the number of protons. Since all isotopes have 1 proton:
- For Protium:
\[ N = 1 - 1 = 0 \]
- For Deuterium:
\[ N = 2 - 1 = 1 \]
- For Tritium:
\[ N = 3 - 1 = 2 \]

4. **Summarize the Number of Protons and Neutrons**:
- Protium: 1 proton, 0 neutrons
- Deuterium: 1 proton, 1 neutron
- Tritium: 1 proton, 2 neutrons

5. **Calculate the Total Number of Protons and Neutrons**:
Now, we sum the number of protons and neutrons for all three isotopes:
\[ \text{Total Protons} = 1 + 1 + 1 = 3 \]
\[ \text{Total Neutrons} = 0 + 1 + 2 = 3 \]
\[ \text{Total (Protons + Neutrons)} = 3 + 3 = 6 \]

6. **Final Answer**:
Therefore, the sum of the number of neutrons and protons in the three isotopes of hydrogen is **6**.