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Physics Paper 1 · P4 · Lesson 4.3

Electrons, ions and energy levels

Follow an electron moving, then an electron leaving.

Key ideas1 of 3

Electrons have energy levels

Electrons occupy energy levels at different distances from the nucleus. Absorbing electromagnetic radiation can move an electron to a higher level, farther away.

A hydrogen atom model with its electron at the lower of two drawn energy levels.

The circles represent energy levels, not solid rings.

Next: How the atomic model changed →
Topic resources and sources

Daily 5 · Core exam practice · Higher Tier questions · A4 revision sheet

Lessons 4.1–4.10 cover the core. Lesson 4.11 is Higher Tier only. Daily 5 practises core facts. Answer positions are shuffled on each new attempt; lessons begin with very simple questions.

AQA Combined Science Trilogy specification · 6.4.1.1–6.4.1.2. Original notes, questions and diagrams. Experimental numbers are illustrative.

Photos: Geiger counter by Boffy b, enhanced by Marco Plassio; caesium source by Wusel007, enhanced by Partynia, both CC BY-SA 3.0. Rutherford at McGill, 1905, unknown photographer / Wellcome Images, public domain. Photos displayed without cropping or other alterations.