Electron Configuration
Electron configuration describes how electrons are arranged in shells around the nucleus, filling from the inside outwards.
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Electron configuration describes how electrons are arranged in shells around the nucleus, filling from the inside outwards.
- First shell holds 2 electrons
- Second and third shells hold 8
- Outer electrons decide chemical behaviour
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Electron Configuration?
Within Chemistry, which covers atoms, bonding, reactions, the periodic table, organic chemistry and the chemistry of everyday life, this topic explains Electron Configuration. Chemistry links what you can see in the lab to the particles and bonds behind it, so each topic here shows that link in a model.
Check that you can explain Electron Configuration in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Electron Configuration helps you explain why substances behave as they do, from cleaning products and food to medicines.
Electron Configuration in detail
Electrons occupy shells around the nucleus, with the first holding up to 2 electrons, and the second and third up to 8. For example, sodium (atomic number 11) is written 2,8,1 and chlorine 2,8,7.
The outer-shell electrons determine how an element reacts, and elements in the same group have the same number of outer electrons. Atoms gain, lose or share electrons to obtain a full outer shell, like the noble gases, which explains ionic and covalent bonding. Electron configuration also explains patterns in reactivity across the periodic table.
How the interactive helps you understand Electron Configuration
Watch the atom model in the interactive. Use any sliders or buttons it offers to change the values and see how the atom model responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Electron Configuration.
Real-life uses and examples
- Explain Electron Configuration in an exam by linking the particles involved to what you observe.
- Use Electron Configuration to explain what happens in a lab experiment and why.
- Link Electron Configuration to everyday products such as cleaning agents, food and medicines.
Common mistakes to avoid
- Mixing up the names of substances or ions when you describe Electron Configuration.
- Describing what happens without explaining the particles or bonds involved.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Electron Configuration
What is Electron Configuration?
Electron configuration describes how electrons are arranged in shells around the nucleus, filling from the inside outwards.
What are the most important points about Electron Configuration?
The main points are: First shell holds 2 electrons; Second and third shells hold 8; Outer electrons decide chemical behaviour.
Why is Electron Configuration useful?
Understanding Electron Configuration helps you explain why substances behave as they do, from cleaning products and food to medicines.
How can I practise Electron Configuration?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Electron Configuration?
Related topics in Chemistry include The Periodic Table, Group 7: Halogens, Metals and Non-Metals.