A scientist reviews evidence about the development of the Periodic Table.
Statement 1: Gallium having properties close to those predicted by Mendeleev provided evidence that leaving gaps was justified.
Statement 2: The existence of isotopes helps to explain why relative atomic mass does not always increase in atomic number order.
Statement 3: Mendeleev separated elements with similar properties whenever their atomic masses were not consecutive.
Statement 4: Moseley refined the table by arranging the elements in order of relative atomic mass rather than atomic number.
Which statements are correct?
2 and 4 only
1, 2 and 4 only
1 and 2 only
1 and 3 only
122 exam-style questions on OCR GCSE Chemistry 2.2 Bonding, covering 2.2.1 Metals, non-metals and the Periodic Table, 2.2.2 Types of chemical bonding and dot and cross diagrams, 2.2.3 Limitations of bonding models, and 2.2.4 Reactivity, atomic number and the modern Periodic Table. Each one has a worked solution and a mark scheme showing where the marks go.