← Chemistry syllabus

WalesChemistry

Unit 1.2 Atomic structure and the Periodic Table

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What is inside an atom, and how do isotopes give an element its relative atomic mass?

Describe sub-atomic particles and their relative masses and charges, work out particle numbers from atomic and mass number, define isotopes, and calculate relative atomic mass.
A focused answer to WJEC GCSE Chemistry topic 1.2, covering protons, neutrons and electrons and their relative masses and charges, atomic number and mass number, working out particle numbers for atoms and ions, isotopes, and calculating relative atomic mass.
9 min answer →

How do we represent chemical reactions, and why is mass always conserved?

Represent reactions by word and balanced symbol equations, apply the law of conservation of mass, and classify reactions as exothermic or endothermic.
A focused answer to WJEC GCSE Chemistry topic 1.1, covering word and balanced symbol equations, the law of conservation of mass, state symbols, and identifying exothermic and endothermic reactions from energy transfer.
9 min answer →

How does paper chromatography separate a mixture, and how do we read a chromatogram?

Carry out paper chromatography, interpret chromatograms, and calculate and use Rf values to identify substances in a mixture.
A focused answer to WJEC GCSE Chemistry topic 1.1, covering the method for paper chromatography, why components separate, how to interpret a chromatogram, and how to calculate Rf values to identify substances.
8 min answer →

How are electrons arranged in shells, and how does this link to the Periodic Table?

Describe the arrangement of electrons into shells for the first twenty elements and relate electronic structure to group and period in the Periodic Table.
A focused answer to WJEC GCSE Chemistry topic 1.2, covering how electrons fill shells, writing the electronic structures of the first twenty elements, and relating the number of outer electrons to group number and the number of shells to period number.
8 min answer →

How do elements, compounds and mixtures differ, and how do we tell a chemical change from a physical one?

Distinguish between elements, compounds and mixtures, interpret chemical formulae, and tell physical changes apart from chemical reactions.
A focused answer to WJEC GCSE Chemistry topic 1.1, covering the difference between elements, compounds and mixtures, reading chemical formulae, and distinguishing physical changes from chemical reactions with evidence such as colour change and gas production.
8 min answer →

How is the Periodic Table organised, and what are the trends in Groups 1, 7 and 0?

Describe the arrangement of the Periodic Table, distinguish metals and non-metals, and explain trends in Group 1, Group 7 and Group 0.
A focused answer to WJEC GCSE Chemistry topic 1.2, covering how the Periodic Table is arranged by atomic number, the difference between metals and non-metals, and the properties and trends of the alkali metals (Group 1), halogens (Group 7) and noble gases (Group 0).
9 min answer →