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4.4 Atomic structure

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What does half-life mean, and how do we use it?

Half-life: the meaning of half-life, calculating activity after a number of half-lives, and the difference between contamination and irradiation.
A focused answer to AQA GCSE Physics 4.4.2, covering the meaning of half-life, how to calculate the remaining activity or number of nuclei after several half-lives, and the difference between radioactive contamination and irradiation.
9 min answer →

What are isotopes and ions, and how do we use atomic and mass numbers?

Isotopes and ions: atomic number and mass number, how isotopes differ, how ions form, and the standard nuclear notation.
A focused answer to AQA GCSE Physics 4.4.1, covering atomic number and mass number, how to read nuclear notation, what makes atoms isotopes of an element, and how atoms become positive or negative ions.
8 min answer →

How is energy released by splitting and by joining nuclei?

Nuclear fission and fusion: the process of fission and the chain reaction, the process of fusion, and how each releases energy (separate physics only).
A focused answer to AQA GCSE Physics 4.4.3, covering nuclear fission as the splitting of a large unstable nucleus, the chain reaction in a reactor, nuclear fusion as the joining of light nuclei in stars, and how each process releases energy.
8 min answer →

What types of nuclear radiation are there, and how do they differ?

Radioactive decay and nuclear radiation: the nature of alpha, beta and gamma radiation and neutron emission, their penetrating and ionising powers, and decay equations.
A focused answer to AQA GCSE Physics 4.4.2, covering radioactive decay as a random process, the nature of alpha, beta, gamma and neutron radiation, their relative ionising and penetrating powers, and how to balance nuclear decay equations.
9 min answer →

What is an atom made of, and how did our model of it develop?

The structure of the atom: the sizes and charges of protons, neutrons and electrons, the nuclear model, and how the model developed from the plum pudding model.
A focused answer to AQA GCSE Physics 4.4.1, covering the relative sizes and charges of protons, neutrons and electrons, the nuclear model of the atom, and how the alpha scattering experiment replaced the plum pudding model.
8 min answer →