There are 14 protons and 13 neutrons in the nucleus of an atom. What is its mass number ?

Answer

To find the mass number of an atom, you can follow these steps:

### Step 1: Identify the number of protons and neutrons
In this case, we are given:
- Number of protons = 14
- Number of neutrons = 13

### Step 2: Use the formula for mass number
The mass number (A) is calculated using the formula:
\[ A = \text{Number of protons} + \text{Number of neutrons} \]

### Step 3: Substitute the values into the formula
Now, substitute the values we identified:
\[ A = 14 + 13 \]

### Step 4: Perform the addition
Now, perform the addition:
\[ A = 27 \]

### Conclusion
The mass number of the atom is 27.

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