Describe the plum pudding model of the atom.
Write the three subatomic particles (electrons, neutrons, and protons) in order of their discovery, from earliest to latest.
The discovery of isotopes explained why some relative atomic masses are not whole numbers.
Element QQQ has two isotopes. The table below shows the mass numbers and percentage abundances of the isotopes of element QQQ.
| Mass number | Percentage abundance (%) |
|---|---|
| 69 | 60.1 |
| 71 | 39.9 |
Calculate the relative atomic mass (ArA_rAr) of element QQQ. 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.