IP Chemistry Upper Sec 08: Patterns in the Periodic Table

For Integrated Programme students: Your current school materials, teacher instructions, and assessment scope take precedence because IP topic sequence and depth vary by school. This is an Eclat IP guide, not the O-Level / SEC G3 exam-track guide.

The core idea is simple: Periodic-table patterns come from proton number and valence electrons.

Use it as a working check: Period tells you shell number. Group tells you valence electrons and common ion behaviour. Trends then explain reactivity, oxide character, and displacement.

Then go one layer deeper: Example: chlorine displaces bromide because chlorine is the more reactive halogen, but iodine cannot displace chloride from a chloride solution.

How this chapter applies

• Eclat blended core: periodic position, valence electrons, Groups 1, 17, and 18, transition elements, the reactivity series, extraction, thermal stability, rusting, and protection are taught as one connected inorganic route.
• School-sensitive extension: ionisation-energy trends, detailed Period 3 structure and oxide or chloride chemistry, and electrochemical rust mechanisms should be used only where the current school teaches them.
• 2027 national comparison: K324 Topic C8 covers the periodic, group, transition-element, reactivity-series, extraction, carbonate, rusting, and sacrificial-protection core.
• Check your school: group numbering, trend explanations, data-book expectations, and the set of Period 3 reactions can differ. Follow the current school sequence and notation.
• Exam-track route: use the separate O-Level and SEC G3 Chemistry notes for K324 topic ownership.

What you must know

• Elements arranged by increasing proton number; period number = number of shells, group number = valence electrons → common ion charge and metallic vs non-metallic character.
• Across a period: metallic to non-metallic; basic oxides → amphoteric → acidic; ionic → giant covalent → simple molecular structures.
• Group 1: soft, low density, mp decreases down group; react with water to form hydroxide + hydrogen (fizzing, floats, lilac flame for K). Down the group reactivity increases.
• Group 17: coloured diatomic molecules (F₂ pale yellow gas, Cl₂ greenish-yellow gas, Br₂ red-brown liquid, I₂ grey-black solid with purple vapour); reactivity decreases down the group; halogen displacement reactions follow reactivity.
• Group 18: full valence shell → very unreactive; uses for inert atmosphere (argon in lamps, helium in balloons).
• Transition elements: higher mp/density than Group 1, variable oxidation states, coloured compounds/ions, good catalysts (Fe in Haber, Ni in hydrogenation).