Each atom/element has an electron configuration
The electron configuration shows the energy level of the electron
Each electron configuration has 4 quantum numbers, namely n, l, ml, and ms
- n = the principal
- l = the angular momentum / azimuthal
- ml = the magnetic
- ms = the electron-spin
We make an example of the element Mg which is in group 2 with the atomic number 12
Electron configuration of Mg: [Ne] 3s² or 1s² 2s² 2p⁶ 3s²
if Mg removes 2 electrons then Mg will form a positive ion (cation) Mg²⁺
This cation is included in the monatomic ion because it is formed from one element (in contrast to the polyatomic ion, which is formed from two or more elements such as SO₄²⁻, ClO₃⁻)
Electron configuration of Mg²⁺ : 1s² 2s² 2p⁶
So atoms can be positively or negatively charged depending on removing or attracting electrons