Studyit

How do you find the number of electrons in an element?

I know that the number of protons is the atomic number but I don’t understand
how to find the number of electrons

Hi Char1lotte

The number of protons is always equal to the number of electrons for elements (atoms) on your periodic table.

This is why atoms are “neutral” (equal number of protons and electrons)
For example, Lithium has 3 protons, hence it will have 3 electrons as well.

When atoms become ions, they will lose or gain electron(s), NOT protons (because the protons are locked in the nucleus of the atom.
For example, if we go back to Lithium, since Lithium has 3 electrons, it’s electron arrangement is 2.1.
The valence electron is 1 (this is the electron in the most outer shell)
When Lithium atom loses an electron to become Lithium ion, it will have an overall charge of +1.
This is because Lithium ion will have 1 proton more than electron (since it’s lost an electron) to become an ion.

You can find more revision materials here:
http://www.nobraintoosmall.co.nz/html/Level1_science/NCEA1_science_acids_bases.html

Hope that was helpful! :slight_smile:

2 Likes