If `U_92^236` nucleus emits one `alpha`-particle, the remaining nucleus will have

Options

A. 119 neutrons and 119 protons
B. 142 neutrons and 90 protons
C. 144 neutrons and 92 protons
D. 146 neutrons and 90 protons

Answer

To solve the problem, we need to determine the number of protons and neutrons in the remaining nucleus after a uranium-236 nucleus emits an alpha particle.

### Step-by-Step Solution:

1. **Identify the Initial Nucleus**:
The given nucleus is Uranium-236, represented as \( _{92}^{236}U \). Here, 92 is the atomic number (number of protons) and 236 is the mass number (total number of protons and neutrons).

2. **Understand Alpha Particle Emission**:
An alpha particle is represented as \( _{2}^{4}He \), which consists of 2 protons and 2 neutrons. When an alpha particle is emitted, the remaining nucleus will lose these particles.

3. **Calculate the Remaining Atomic Number**:
The atomic number of the remaining nucleus after emitting an alpha particle can be calculated as follows:
\[ \text{Remaining atomic number} = \text{Initial atomic number} - \text{Protons in alpha particle} \]
\[ \text{Remaining atomic number} = 92 - 2 = 90 \]

4. **Calculate the Remaining Mass Number**:
The mass number of the remaining nucleus can be calculated as follows:
\[ \text{Remaining mass number} = \text{Initial mass number} - \text{Mass number of alpha particle} \]
\[ \text{Remaining mass number} = 236 - 4 = 232 \]

5. **Determine the Number of Neutrons in the Remaining Nucleus**:
The number of neutrons can be calculated using the formula:
\[ \text{Number of neutrons} = \text{Mass number} - \text{Atomic number} \]
\[ \text{Number of neutrons} = 232 - 90 = 142 \]

6. **Final Result**:
Therefore, the remaining nucleus after the emission of the alpha particle will have:
- Protons: 90
- Neutrons: 142

### Conclusion:
The remaining nucleus after the emission of one alpha particle from Uranium-236 will have 90 protons and 142 neutrons.