GCSE Chemistry Paper 1 Overview

Topics Covered

• Key Concepts
• States of Matter
• Chemical Changes
• Extracting Metals and Equilibria
• Special Topic for Triple Chemistry: Nanoparticles and Allotropes

Key Concepts

Atoms and Elements

• Substances are made of atoms, represented by symbols in the periodic table.
• Compounds consist of two or more different atoms chemically bonded, e.g., water (H₂O).
• Chemical reactions change how atoms are bonded.

Chemical Equations

• Atoms are not created or destroyed in reactions; equations must be balanced.
• Tips for balancing: start with atoms in only compounds, balance those first.

Models of the Atom

• JJ Thompson: Plum Pudding Model with positive and negative charges.
• Ernest Rutherford: Discovered nucleus; atoms mostly empty space.
• Neils Bohr: Electrons exist in shells.
• James Chadwick: Discovered neutrons.

Periodic Table

• Atomic number (number of protons) determines the element.
• Mass number = protons + neutrons.
• Isotopes: same number of protons, different number of neutrons.
• Elements organized by atomic weight initially, later by properties (Mendeleev).

Electron Configuration

• Electrons fill shells from inside out (2, 8, 8, 2 for first 20 elements).
• Metals donate electrons; non-metals accept electrons.
• Groups indicate the number of electrons in the outer shell.

States of Matter

States

• Solid, liquid, gas
• Changes of state are physical changes, not chemical.

Properties

• Solids: Vibrate in fixed positions.
• Liquids: Particles move past each other while touching.
• Gases: Particles far apart and move randomly.

Chemical Changes

Reactions and Bonds

• Ionic bonding: metal and non-metal exchange electrons.
• Covalent bonding: non-metals share electrons.
• Metallic bonding: lattice of ions with delocalized electrons.

Ionic Compounds

• High melting/boiling points due to strong electrostatic forces.
• Conduct electricity when molten or in solution.

Covalent Compounds

• Low boiling points due to weak intermolecular forces.
• Cannot conduct electricity.

Extracting Metals

Reactivity Series

• More reactive metals displace less reactive ones from compounds.
• Displacement reactions and electrolysis used for extraction.

Electrolysis

• Involves passing current through molten compounds to separate elements.

Equilibria

Reversible Reactions

• Products can revert to reactants.
• Equilibrium reached when forward and reverse reactions occur at the same rate.

Le Chatelier's Principle

• Systems adjust to counteract changes (e.g., pressure, concentration, temperature).

Special Topics for Triple Chemistry

Nanoparticles

• Structures between 1-100 nanometers.
• High surface area to volume ratio allows for fewer materials needed.

Allotropes of Carbon

• Diamond, graphite, graphene, fullerenes (nanotubes and buckyballs).
• Different properties due to different bonding arrangements.