How To Draw A Shell Diagram

Boost your 14–16 students' confidence drawing electron configuration diagrams with these easy to follow steps

An electron configuration diagram is a model that depicts the position of electrons as they orbit the nucleus of an atom. Electrons are represented by dots or crosses and are positioned in energy levels, or 'shells', around the central nucleus. This is sometimes called the Bohr, or the 'solar system', model.

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This infographic is designed to be displayed as a poster in the classroom, although it can also be displayed on a projector or printed as a handout.

Use the accompanying fact sheet and worksheet to get your students drawing electron configuration diagrams.

Poster with the atomic number at the top as pdf (A4 single pages or A3 one page)
Poster with the atomic number at the bottom as pdf (A4 single pages or A3 one page)
Fact sheet as MS Word or pdf
Configuration confusion student worksheet as MS Word or pdf
Configuration confusion answers as MS Word or pdf

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In the Bohr model, there are a few rules that will help you draw accurate diagrams.

Electrons must occupy the lowest available shell, closest to the nucleus.
The maximum number of electrons that can fill each shell is:
- two in the first shell,
- eight in the second shell,
- eight in the third shell.
Calcium, the 20^th element, has two further electrons that go in the fourth shell.

In the shorthand notation for electron configuration, the number of electrons in each shell can be written rather than drawn. Each shell is separated by a full stop or a comma. For nitrogen this would be 2.5 or 2,5 and for calcium this would be 2.8.8.2 or 2,8,8,2.

Did you know …?

The arrangement of an element's electrons tells you where it is on the periodic table. The number of shells shows which period, or row, it's in and the number of electrons in the outer shell shows which group it's in.

How to draw an electron configuration diagram

Now draw the first 20 elements

Kirsty Patterson is the assistant editor for teaching resources at the Royal Society of Chemistry.