Ne nucleus , the after absorbing energy , decays into two `alpha` particle and an unknown nucleus . The unknown nucleus is

Options

A. nitrogen
B. carbon
C. boron
D. oxygen

Explanation

To solve the problem, we need to identify the unknown nucleus that results from the decay of a given nucleus into two alpha particles. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the decay process
The problem states that a nucleus (let's denote it as N) decays into two alpha particles and an unknown nucleus (X). An alpha particle has a mass number of 4 and an atomic number of 2.

### Step 2: Define the known quantities
Let’s denote the mass number of the original nucleus N as A and its atomic number as Z. According to the problem, we have:
- Mass number (A) = 22
- Atomic number (Z) = 10

### Step 3: Write the decay equation
The decay can be represented as:
\[ N \rightarrow 2 \alpha + X \]
Where \( \alpha \) represents the alpha particles.

### Step 4: Calculate the mass number of the unknown nucleus
The total mass number before decay must equal the total mass number after decay:
\[ A = A_{\alpha_1} + A_{\alpha_2} + A_X \]
Where:
- \( A_{\alpha_1} = 4 \) (mass number of the first alpha particle)
- \( A_{\alpha_2} = 4 \) (mass number of the second alpha particle)
- \( A_X \) is the mass number of the unknown nucleus.

Substituting the values:
\[ 22 = 4 + 4 + A_X \]
\[ 22 = 8 + A_X \]
\[ A_X = 22 - 8 = 14 \]

### Step 5: Calculate the atomic number of the unknown nucleus
Similarly, the total atomic number before decay must equal the total atomic number after decay:
\[ Z = Z_{\alpha_1} + Z_{\alpha_2} + Z_X \]
Where:
- \( Z_{\alpha_1} = 2 \) (atomic number of the first alpha particle)
- \( Z_{\alpha_2} = 2 \) (atomic number of the second alpha particle)
- \( Z_X \) is the atomic number of the unknown nucleus.

Substituting the values:
\[ 10 = 2 + 2 + Z_X \]
\[ 10 = 4 + Z_X \]
\[ Z_X = 10 - 4 = 6 \]

### Step 6: Identify the unknown nucleus
Now we have:
- Mass number \( A_X = 14 \)
- Atomic number \( Z_X = 6 \)

We can now identify the unknown nucleus. The nucleus with atomic number 6 and mass number 14 is Carbon (C).

### Conclusion
The unknown nucleus is Carbon (C).