‹ Chemistry simulationsChemistry · AS Level 9701 · 9 PeriodicityFive simulations covering Topic 9: the trends in atomic radius, ionisation energy, melting point, electronegativity and conductivity across period 3, the structure and bonding behind the melting points, the acid-base character of the period 3 oxides, the hydrolysis of the chlorides, and the two dips in the ionisation energy pattern.
Across a period the nuclear charge rises while the electrons go into the same shell, so the attraction on the outer electrons grows. Pick a property and watch the bars change; the explanation underneath says why.
The melting points across period 3 make no sense until you look at the structures. Three giant metallic lattices, one giant covalent, three simple molecular solids and a monatomic gas. Rotate each one and read its melting point off the graph.
Metal oxides on the left are ionic and basic, the oxide in the middle is amphoteric, and the non-metal oxides on the right are covalent and acidic. Drop each one into water and read the pH.
Ionic chlorides dissolve to give neutral solutions; covalent chlorides are hydrolysed, giving fumes of hydrogen chloride and a strongly acidic solution. Add each to water and see which fumes.
First ionisation energy rises across a period, but there are two small dips. Each one is evidence for the sub-shell structure of the atom. Click an element to see its outer configuration and why it sits where it does.
3D bar charts of atomic radius, ionisation energy, melting point, electronegativity and conductivity across period 3, the giant metallic, giant covalent, simple molecular and monatomic structures behind the melting points, the oxides from basic through amphoteric to acidic with pH, the chlorides and their hydrolysis, and first ionisation energies with the two sub-shell dips explained.
Five simulations covering Topic 9: the trends in atomic radius, ionisation energy, melting point, electronegativity and conductivity across period 3, the structure and bonding behind the melting points, the acid-base character of the period 3 oxides, the hydrolysis of the chlorides, and the two dips in the ionisation energy pattern.
Periodicity is a free, browser-based simulation for Cambridge International AS & A Level Chemistry 9701 (topic 9 The Periodic Table: chemical periodicity). The same ideas are examined in Cambridge IGCSE Chemistry 0620 (topic 7 Acids, bases and salts, topic 8 The Periodic Table). The course is assessed in Paper 1 (Multiple Choice (AS)), Paper 2 (AS Structured), Paper 3 (Advanced Practical), Paper 4 (A Level Structured), Paper 5 (Planning, Analysis, Evaluation). Syllabus for examination in 2025-2027. There are 5 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.
Full syllabus map: AS Level Chemistry 9701 topic 9.
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