Writing and drawing electronic configuration

Take sodium as an example. Sodium has 11 electrons. It has:

  • 2 electrons in the first shell
  • 8 electrons in the second shell
  • 1 electron in the third shell

You can write sodium’s electronic configuration with numbers and commas: 2,8,1

The electronic configuration of sodium can be shown in a diagram. The dots represent electrons. Electrons may be shown using dots or crosses.

Structure of a sodium atomA diagram of the electronic configuration of an atom of sodium.