3 x 1 hour lessons

This module introduces the fundamental structure of atoms, including protons, neutrons, and electrons. You’ll learn how to calculate the number of subatomic particles in atoms and ions using atomic and mass numbers, and how to distinguish between different isotopes.

You’ll also practise calculating relative atomic mass from isotopic abundances — a key skill for exam questions and quantitative chemistry. The module then explores how electrons are arranged in shells, sub-shells, and orbitals. You’ll learn how to write electron configurations for atoms and ions using s, p, and d notation, and see how this links to the layout of the periodic table.

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By the end of this module, you'll be able to:

• Define atomic number, mass number, and isotope

• Calculate the number of protons, neutrons, and electrons in atoms and ions

• Calculate relative atomic mass from isotopic data

• Write electron configurations for atoms and ions using sub-shell notation

• Understand how the periodic table reflects electron arrangement

OCR (A) specification points covered: 2.1.1 Atomic structure and isotopes 2.2.1 Electron structure