How do you find the number of neutrons in an element on the periodic table?

2 Answers
Mar 6, 2018

To find the neutrons in an element of the periodic table, you need two things, the atomic number of the element and the atomic mass of that element. See below

Explanation:

The atomic number represents the amount of protons in an element and is on top of the symbol for that element...this is always a whole number

Right below the chemical symbol, you will find a number that usually has decimals and is not a whole number...this is the atomic mass of the element and it represents the number of protons and neutrons in the element, the reason why it does not also account for the electrons is because the electron mass is negligible....

So right now you have two things: the number of protons in the element, and the combined number of protons and neutrons in that element...so how would you find just the number of neutrons

Rounded Atomic Mass to the whole number - the Atomic Number= Number of Neutrons of the element

Mar 6, 2018

(Relative atomic mass) minus (atomic number)

Explanation:

The atomic number is the number of protons OR electrons. They are both equal thus making the atom have a neutral charge.

The relative atomic mass is the number of protons AND neutrons.

You subtract the atomic number from the atomic mass to find the number of neutrons alone.