# What is the number of protons, neutrons, and electrons in ""_18^40Ar?

Mar 26, 2018

$18$ protons, $18$ electrons, and $22$ neutrons.

#### Explanation:

In the form of an element, ""_Z^YX, $Z$ is the number of protons, and also the number of electrons, and $Y$ is the atomic mass.

So, in the case of ""_18^40Ar, then it has $18$ protons and $18$ electrons.

The number of neutrons is given by subtracting the atomic mass from the proton number. So here, $Y = 40$, and the number of neutrons is:

$Y - Z$

$= 40 - 18$

$= 22$