Chemistry Past Papers

Edexcel IGCSE Chemistry has 5 sections: Section 1 (Principles of Chemistry — states of matter, atomic structure, bonding, electrolysis), Section 2 (Inorganic Chemistry — groups 1 & 7, reactivity, extraction), Section 3 (Physical Chemistry — energetics, rates, equilibrium), Section 4 (Organic Chemistry — alkanes, alkenes, polymers), Section 5 (Chemistry in Society — atmosphere, water, industrial chemistry).

To balance equations: 1) Write the unbalanced equation, 2) Count atoms of each element on both sides, 3) Add coefficients to balance atoms (never change subscripts), 4) Check all atoms are balanced.

The reactivity series orders metals by reactivity: K, Na, Ca, Mg, Al, C, Zn, Fe, Pb, H, Cu, Ag, Au (most to least reactive). More reactive metals displace less reactive ones from solutions and react more vigorously with acid and water.

Edexcel IGCSE Chemistry has two papers: Paper 1 (2 hours, 110 marks) and Paper 2 (1 hour 15 minutes, 70 marks). Both are written exams covering all topics.

Ionic bonding involves transfer of electrons between metals and non-metals, forming charged ions held by electrostatic attraction in a lattice. Covalent bonding involves sharing of electrons between non-metals, forming molecules or giant covalent structures.