Describe the "plum pudding" model of the atom, detailing how charge and mass were thought to be distributed.
Write the three subatomic particles (electrons, neutrons, and protons) in chronological order of their discovery, from earliest to latest.
The discovery of isotopes explained why measured relative atomic masses of elements are often not whole numbers.
Naturally occurring antimony consists of two stable isotopes, 121Sb^{121}\text{Sb}121Sb and 123Sb^{123}\text{Sb}123Sb. The table below shows the mass numbers and percentage abundances of these two isotopes.
| Isotope | Mass number | Percentage abundance (%) |
|---|---|---|
| 121Sb^{121}\text{Sb}121Sb | 121 | 57.2 |
| 123Sb^{123}\text{Sb}123Sb | 123 | 42.8 |
Calculate the relative atomic mass (ArA_rAr) of antimony. 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.