The number of neutrons in an atom is equal to _

The number of neutrons in an atom is equal to __. the mass number the mass number + the atomic number the number of protons the mass number – the atomic number the atomic number

The Correct Answer and Explanation is:

The correct answer is: the mass number – the atomic number.

To explain this, let’s break it down.

1. Atomic Number: This refers to the number of protons in the nucleus of an atom. It defines the element. For example, carbon has an atomic number of 6, meaning it has 6 protons.
2. Mass Number: The mass number is the total number of protons and neutrons in the nucleus of an atom. For example, carbon-12 has a mass number of 12, which means it has 6 protons and 6 neutrons (because the mass number is the sum of protons and neutrons).

Now, to find the number of neutrons, we subtract the atomic number (which tells us the number of protons) from the mass number (which tells us the total number of protons and neutrons).

For example, if we look at an atom of carbon-12:

• The atomic number of carbon is 6 (it has 6 protons).
• The mass number of carbon-12 is 12.

To calculate the number of neutrons: Neutrons=Mass number−Atomic number=12−6=6\text{Neutrons} = \text{Mass number} – \text{Atomic number} = 12 – 6 = 6Neutrons=Mass number−Atomic number=12−6=6

Therefore, carbon-12 has 6 neutrons. This formula works for any element. For instance, if we take oxygen-16:

• The atomic number of oxygen is 8.
• The mass number of oxygen-16 is 16.

Neutrons=16−8=8\text{Neutrons} = 16 – 8 = 8Neutrons=16−8=8

So, oxygen-16 has 8 neutrons.

This shows how the mass number and atomic number are related, and how you can easily calculate the number of neutrons in an atom.