An isotope of atomic mass `25` has `13` neutrons in its neucleus .What is its atomic number and what are the name and chemicalsymbol of the element ?

Explanation

To solve the problem, we need to determine the atomic number, name, and chemical symbol of an isotope with an atomic mass of 25 and 13 neutrons. Here’s the step-by-step solution:

### Step 1: Understand the relationship between atomic mass, protons, and neutrons.
The atomic mass (A) of an element is the sum of the number of protons (Z) and neutrons (N) in its nucleus. This can be represented by the formula:
\[ A = Z + N \]

### Step 2: Identify the given values.
From the problem:
- Atomic mass (A) = 25
- Number of neutrons (N) = 13

### Step 3: Rearrange the formula to find the atomic number (Z).
We can rearrange the formula to find the number of protons (Z):
\[ Z = A - N \]

### Step 4: Substitute the known values into the equation.
Now, substitute the values we have into the equation:
\[ Z = 25 - 13 \]
\[ Z = 12 \]

### Step 5: Identify the element based on the atomic number.
The atomic number (Z) of 12 corresponds to the element magnesium.

### Step 6: Write down the chemical symbol.
The chemical symbol for magnesium is Mg.

### Final Answer:
- Atomic Number (Z) = 12
- Element Name = Magnesium
- Chemical Symbol = Mg

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