Mendeleev predicted the properties of an undiscovered element from
a complete knowledge of electron shells
the properties of nearby elements in the same group
the number of neutrons in its most common isotope
the colour of its compounds only
80 exam-style questions on Edexcel GCSE Chemistry 2.2 The periodic table, covering 2.2.1 Mendeleev's periodic table, 2.2.2 Periods, groups, metals and non-metals, and 2.2.3 Electronic configuration and position in the periodic table. Each one has a worked solution and a mark scheme showing where the marks go.