# Given an element’s atomic number and mass number, how can you tell the number of protons and neutrons in its nucleus?

Given an element’s atomic number and mass number, how can you tell the number of protons and neutrons in its nucleus?

## This Post Has 8 Comments

1. ajayfurlow says:

Explanation: When looking at a periodic table, the atomic number tells you the element’s identity as well as atomic number. For neutrons, you have to subtract the atomic number from the mass.

2. shealwaysknows23 says:

Explanation:

Atomic number is the number of protons present in an atom. Whereas mass number is the sum of total number of protons and neutrons present in an atom.

For example, atomic number of bromine is 35, that is, there are 35 protons present in a bromine atom. The mass number of bromine is 80.

So,     Mass number = no. of protons + no. of neutrons

no. of neutrons = mass number - no. of protons

= 80 - 35

= 45

Hence, in a bromine atom there are 35 protons and 45 neutrons.

3. valeriearras says:

The answer more than likely based on research would be (B.)

4. th483 says:

The mass number of an element tells you the total number of nucleons (neutrons and protons) the element has, while the atomic number only tells you the amount of protons.
Hope this helps.

5. Ronatalawrence828 says:

Are there any choices or is that the only part of the question?

6. avision42 says:

It would be the first option.

Explanation-
The number of protons is equal to the atomic number the number of neutrons is the mass minus the atomic number.

7. datboi995 says:

I would explain why I am correct but the answer is the explanation lol.

I hope this helped.

8. allykram7 says:

Number of protons = atomic number; number of neutrons = mass number - atomic number

Explanation:

Z = atomic number = number of protons

A = mass number = number of protons + number of neutrons

Mass number = atomic number + number of neutrons

Number of neutrons = mass number - atomic number

$Siven an element's atomic number and mass number, how can you tell the number of protons and neutron$