Atomic structure - (CCEA)Writing and drawing electronic configuration

Atoms have a positively-charged nucleus made of protons and neutrons, and negatively-charged electrons that orbit the nucleus in shells.

Part ofCombined ScienceStructures, trends, chemical reactions, quantitative chemistry and analysis

Writing and drawing electronic configuration

Take sodium as an example. Sodium has 11 . 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 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 atom
Figure caption,
A diagram of the electronic configuration of an atom of sodium.