How to Write Electron Configurations for Atoms of Any Element
Step 1: Find out how many electrons the atom has. On the periodic table, the atomic number is the number of protons of the atom, and thus equals the number of electrons in an atom with zero charge.
Step 2: Once you know the number of electrons, begin filling them in the orbitals. Put one electron in the lowest energy level starting with 1s.
Electrons are filled in the following order.
o Note: Energy level changes as you go up. For example, when you are about to go up to the 4th energy level, it becomes 4s first, then 3d. After that it follows the order once again. This only happens after the 3rd energy level!
Step 3: Once you have placed your electrons in the correct order. Write the electron configuration down.