EdEXL GCSE Chemistry Paper 1 - Key Concepts

Topics to be Covered

• States of Matter
• Chemical Changes
• Extracting Metals
• Equilibria
• Special Triple Separate Chemistry

Basic Concepts

• Atoms and Elements: Atoms are the building blocks of substances. Elements are types of atoms represented by symbols in the periodic table.
• Compounds: Contain two or more different atoms chemically bonded (e.g., H₂O for water).
• Chemical Reactions: Atoms change bonds through reactions, represented by word and chemical equations.
• Balancing Equations: Ensure same number of each type of atom on both sides of a reaction.

History of Atomic Theory

• JJ Thomson: Discovered atoms have charges, proposed plum pudding model.
• Ernest Rutherford: Discovered nucleus; atoms mostly empty space.
• Neils Bohr: Electrons in shells.
• James Chadwick: Discovered neutrons.

The Periodic Table

• Atomic Number: Number of protons.
• Mass Number (RAM): Protons + Neutrons.
• Isotopes: Atoms with the same number of protons but different neutrons.
• Periodic Table Structure: Organizes elements by similar properties.

Electron Configuration

• Electrons fill shells in the sequence 2, 8, 8, 2.
• Metals vs. Non-Metals: Metals donate electrons; non-metals accept.
• Groups and Periods: Indicate valence electrons and energy levels.

Bonding

• Ionic Bonding: Transfer of electrons between metals and non-metals. Compounds must be electrically neutral.
• Covalent Bonding: Sharing of electrons between non-metals.
• Metallic Bonding: Lattice structure with delocalized electrons.

Structure and Properties

• Ionic Compounds: High melting/boiling points; conduct electricity when molten.
• Covalent Structures: Low melting points for simple structures; vary for giant structures like diamond.
• Metals and Alloys: Conduct electricity; alloys disrupt lattice to enhance strength.

Chemical Calculations

• Moles: Unit to measure substance amount.
• Concentration: Amount of solute in a given volume of solution (mol/dm³).
• Stoichiometry: Ratios of reactants and products in a balanced equation.

Chemical Reactions

• Reactivity Series: Metal displacement based on reactivity.
• Extraction of Metals: Smelting and electrolysis.
• Corrosion and Prevention: Rusting in iron; use of sacrificial metals.

Equilibria

• Reversible Reactions: Products can revert to reactants.
• Equilibrium: No net change in reactants/products in a closed system.
• Le Chatelier's Principle: System compensates for changes in conditions.

Environmental Chemistry

• Life Cycle Assessment: Evaluates product's environmental impact.
• Recycling: Reduces environmental impact of raw material extraction.

Advanced Topics (Triple Only)

• Titration: Determines concentration of acids/alkalis via neutralization.
• Yield and Atom Economy: Measures efficiency and effectiveness of reactions.
• Fuel Cells: Convert chemical energy into electricity, e.g., hydrogen fuel cells.

This summary covers key points for EdEXL GCSE Chemistry Paper 1. Focus on understanding the basic concepts, calculations, and applications in real-world scenarios.