Question

How do we find the number of neutrons in an atom?

Add the atomic number and mass number together
Subtract the number of electrons from the number of protons
Subtract the number of protons from the mass number

Answer 1

To find the number of neutrons in an atom, you should **subtract the number of protons from the mass number**.

Here's how it works:

1. The **mass number** of an atom is the sum of its protons and neutrons.
2. The **atomic number** (which is the number of protons in the nucleus) can be used to determine how many neutrons are present, since:

\[
\text{Number of neutrons} = \text{Mass number} - \text{Number of protons}
\]

So, the correct method is to subtract the number of protons (the atomic number) from the mass number.