Contents
Key Stage 3
Meaning
Electron shells are the places around a nucleus where an electron can orbit the nucleus.
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| A diagram of a Sodium atom shown the electron shells. |
About Electron Shells
- The number of electron shells is shown by the period on the Periodic Table.
- The number of electrons in the outer shell determines the chemical properties of the element.
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| A diagram of the first 20 elements in the Periodic Table showing the electron shells. |
Key Stage 4
Meaning
An electron orbital, also known as an electron shell, are the locations where electrons orbit the nucleus of atoms.
About Electron Orbitals
- Each electron orbital only holds a certain number of electrons.
- These orbitals and the number of electrons in an atom determine the chemistry of an element.
- The number of electron orbitals determines the Period on the Periodic Table.
- The number of electrons in the last orbital (Outer Shell) determines the Group on the Periodic Table.
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| A diagram showing the electron shells and electrons in the first 20 elements on the Periodic Table. NB Group 0 used to be called Group 8 but this caused confusion because most elements in Group 8 have 8 electrons in their Outer Shell but Helium only has 2, so it was renamed Group 0. |
- Atoms in the same group have similar chemical properties because they all have the same number of electrons in their Outer Shell.