The radius of a helium atom is 1.2 × 10-10 m.
The radius of its helium nucleus is 2.4 × 10-15 m.
Calculate the ratio of the radius of the helium atom to the radius of its nucleus. Give your answer as a standard number or in standard form.
81 exam-style questions on Edexcel GCSE Physics 6.1 Atomic structure and isotopes, covering 6.1.1 Structure of the atom, 6.1.2 Isotopes: atomic and mass number, 6.1.3 Sub-atomic particles: masses and charges, and 6.1.4 Electron orbits and energy changes. Each one has a worked solution and a mark scheme showing where the marks go.