Electron Structure
Chemistry: Edexcel IGCSE, topic 4.1.2
Electronic Structure
Electrons have fixed positions in atoms called shells or energy levels. These shells (or energy levels) go around the atom's nucleus.
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Filling electron shells
- Electrons fill an atom's shells in order of increasing energy.
- The closer a shell is to the nucleus, the lower its energy level, so the first shell that is filled is the closest to the nucleus.
Electron configuration
- Electron configuration tells us how an atom's electrons are organised.
- The innershell (closest to the nucleus) can have a maximum of 2 electrons and the next two shells can have a maximum of 8 electrons.
- Any extra electrons are then put into a fourth shell.
Test yourself on Electron Structure
How many more electrons can fit in the 2nd electron shell compared to the 1st?