Two atomic models were used to predict the results of an alpha-scattering experiment. Alpha particles are positively charged.
| Model or experiment | Distribution of charge in the atom | Passed almost straight through | Deflected through a large angle | Bounced almost straight back |
|---|---|---|---|---|
| Model R | Positive charge spread throughout the atom, with negative electrons dotted through it | 20 000 | 0 | 0 |
| Model S | Positive charge concentrated in a tiny central region, with negative electrons outside this region | 19 920 | 74 | 6 |
| Experiment | – | 19 918 | 76 | 6 |
A scientist concludes:
“Model R is the plum pudding model. The experimental results support Model R rather than Model S.”
Evaluate the scientist's conclusion.
Use all three scattering outcomes in the table.
93 exam-style questions on AQA GCSE Chemistry 1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes, covering 1.1.1a Atoms, elements and compounds, 1.1.1b Half equations and ionic equations, 1.1.2 Mixtures, 1.1.3 The development of the model of the atom (common content with physics), 1.1.4 Relative electrical charges of subatomic particles, 1.1.5 Size and mass of atoms, 1.1.6 Relative atomic mass, and 1.1.7 Electronic structure. Each one has a worked solution and a mark scheme showing where the marks go.