Describe the "plum pudding" model of the atom developed by J. J. Thomson.
List the three primary subatomic particles (electrons, neutrons, and protons) in chronological order of their discovery, from earliest to latest.
The existence of isotopes explains why the relative atomic masses of many elements are not whole numbers.
Element Λ\LambdaΛ has two stable isotopes. The table below shows the mass numbers and percentage abundances of the isotopes of element Λ\LambdaΛ.
| Mass number | Percentage abundance (%) |
|---|---|
| 85 | 72.2 |
| 87 | 27.8 |
Calculate the relative atomic mass (ArA_rAr) of element Λ\LambdaΛ. Give your answer to 1 decimal place.
41 exam-style questions on AQA GCSE Chemistry 1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes, covering 1.1.1 Atoms, elements and compounds, 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.