If an isotope of hydrogen has two neutrons in its atom, its atomic number and mass number will respectively be

Options

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

Explanation

To solve the problem of determining the atomic number and mass number of an isotope of hydrogen that has two neutrons, we can follow these steps:

### Step 1: Understand the Basics of Atomic Structure
- The atomic number (Z) of an element is defined as the number of protons in its nucleus.
- The mass number (A) is the total number of protons and neutrons in the nucleus.

### Step 2: Identify the Isotope of Hydrogen
- Hydrogen has three isotopes:
1. Protium (¹H) - 1 proton, 0 neutrons (mass number = 1)
2. Deuterium (²H) - 1 proton, 1 neutron (mass number = 2)
3. Tritium (³H) - 1 proton, 2 neutrons (mass number = 3)

Given that the question specifies an isotope of hydrogen with two neutrons, we are dealing with Tritium.

### Step 3: Determine the Atomic Number
- Since all isotopes of hydrogen have the same atomic number, which is 1 (because they all contain one proton), the atomic number of this isotope is:
\[ \text{Atomic Number (Z)} = 1 \]

### Step 4: Calculate the Mass Number
- The mass number is calculated using the formula:
\[ \text{Mass Number (A)} = \text{Number of Protons} + \text{Number of Neutrons} \]
- For Tritium, we have:
- Number of Protons = 1
- Number of Neutrons = 2
- Therefore, the mass number is:
\[ \text{Mass Number (A)} = 1 + 2 = 3 \]

### Conclusion
- The atomic number of the isotope of hydrogen with two neutrons is 1, and the mass number is 3.

### Final Answer
- Atomic Number: 1
- Mass Number: 3

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