Scientists' ideas about atoms have changed over time. The table shows some important steps.
| Year | Scientist | Discovery or idea |
|---|---|---|
| 1803 | John Dalton | atoms are tiny particles |
| 1897 | J J Thomson | discovered a particle much smaller than an atom |
| 1911 | Ernest Rutherford | nuclear model of the atom |
| 1913 | Niels Bohr | electrons in shells |
| 1932 | James Chadwick | discovered the neutron |
Dalton described atoms as solid spheres. State one other idea Dalton had about atoms.
Name the particle that Thomson discovered in 1897.
Explain how Thomson's discovery showed that one of Dalton's ideas about atoms was wrong.
Describe how Bohr's model of 1913 was different from Rutherford's model of 1911.
Explain why the model of the atom has changed over time.
46 exam-style questions on Edexcel GCSE Chemistry 2.1 Atomic structure, covering 2.1.1 Development of the atomic model, 2.1.2 Structure of the atom and subatomic particles, 2.1.3 Mass number, isotopes and relative atomic mass, and 2.1.4 Calculating relative atomic mass from isotopic abundance. Each one has a worked solution and a mark scheme showing where the marks go.