Which of the following elements has same number of protons, electrons and neutrons?

Options

A. Al
B. Mg
C. P
D. Cl

Explanation

To determine which element has the same number of protons, electrons, and neutrons, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- Protons: Positively charged particles found in the nucleus of an atom. The number of protons is equal to the atomic number (Z).
- Electrons: Negatively charged particles that orbit the nucleus. In a neutral atom, the number of electrons is equal to the number of protons.
- Neutrons: Neutral particles in the nucleus. The number of neutrons can be calculated using the formula:
\[ \text{Neutrons} = \text{Mass Number} - \text{Atomic Number} \]

2. **Identify the Elements**:
- We will check the following elements: Aluminum (Al), Magnesium (Mg), Phosphorus (P), and Boron (B).

3. **Calculate for Aluminum (Al)**:
- Atomic Number (Z) = 13 (protons)
- Mass Number (A) = 27
- Neutrons = 27 - 13 = 14
- Protons = 13, Electrons = 13, Neutrons = 14. (Not equal)

4. **Calculate for Magnesium (Mg)**:
- Atomic Number (Z) = 12 (protons)
- Mass Number (A) = 24
- Neutrons = 24 - 12 = 12
- Protons = 12, Electrons = 12, Neutrons = 12. (All equal)

5. **Calculate for Phosphorus (P)**:
- Atomic Number (Z) = 15 (protons)
- Mass Number (A) = 31
- Neutrons = 31 - 15 = 16
- Protons = 15, Electrons = 15, Neutrons = 16. (Not equal)

6. **Calculate for Boron (B)**:
- Atomic Number (Z) = 5 (protons)
- Mass Number (A) = 11
- Neutrons = 11 - 5 = 6
- Protons = 5, Electrons = 5, Neutrons = 6. (Not equal)

7. **Conclusion**:
- The only element where the number of protons, electrons, and neutrons are the same is Magnesium (Mg).

### Final Answer:
**Magnesium (Mg)** is the element that has the same number of protons, electrons, and neutrons.

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