All of AQA CHEMISTRY Paper 1 in 30 minutes - GCSE Science Revision

AQA GCSE Chemistry Paper 1 Overview

• Topics cover key concepts in Chemistry, suitable for various tiers: higher and foundation tier, double combined, trilogy, and triple separate.

Atoms and Compounds

• Atoms: Basic building blocks of matter, represented in the periodic table by symbols.

• Elements: Different types of atoms depicted as symbols (e.g., H for hydrogen, O for oxygen).

• Compounds: Substances containing two or more different types of atoms chemically bonded together (e.g., H2O has 2 hydrogen atoms and 1 oxygen atom).

• Chemical Reactions: In chemical reactions, atoms are rearranged but not created or destroyed.

• Balancing Equations: Must maintain the same number of each type of atom on both sides; start with compounds, adjust with coefficients (e.g., 2H2O).

Mixtures and Separation Techniques

• Mixtures: Combination of elements and compounds not chemically bonded (e.g., air, saltwater).

• Separation Methods:

  • Filtration: Separates insoluble particles (e.g., sand from water).

  • Crystallization: Solid (solute) separated from solvent (e.g., salt from water).

  • Distillation: Heats solution; gas cools and condenses back into liquid.

  • Fractional Distillation: Separates liquids with different boiling points.

States of Matter

• Three Main States: Solid, liquid, gas.

  • Solid: Particles fixed in place, vibrate.

  • Liquid: Particles close but moving past each other.

  • Gas: Particles far apart, move randomly with high energy.

• Physical Changes: Melting, evaporation require energy; do not create new substances.

Atomic Structure

• Early Theories:

  • JJ Thompson: Plum pudding model with positive charge and negative electrons.

  • Ernest Rutherford: Nucleus concept; atoms mostly empty space.

  • Niels Bohr: Introduced electron shells (orbitals).

  • James Chadwick: Neutron discovery in the nucleus.

• Charges:

  • Protons: +1 charge, mass = 1.

  • Neutrons: 0 charge, mass = 1.

  • Electrons: -1 charge, negligible mass.

The Periodic Table

• Atomic Number: Number of protons determines element identity.

• Mass Number: Total of protons and neutrons (e.g., Carbon-12 has 6 protons and 6 neutrons).

• Isotopes: Atoms with the same element but different neutron counts.

• Average Atomic Mass: Calculated from relative abundance of isotopes

  • Example: Chlorine (75% with mass 35, 25% with mass 37) averages to 35.5.

• Mendeleev's Contribution: Arranged elements by properties, predicting undiscovered elements.

Electron Configuration

• Shells: Organised filling; 2 in first, 8 in second/third, 2 in fourth, max 20.

• Example: Magnesium (12 electrons) configuration is 2, 8, 2.

• Groups in Periodic Table:

  • Group 1 (Alkali Metals): 1 electron in outer shell; increases reactivity down the group.

  • Group 7 (Halogens): 7 electrons in outer shell; decreases reactivity down the group and boiling points increase.

Summary of Important Concepts

• Higher atomic number relates to the number of protons.

• Elements tend to gain, lose, or share electrons to achieve stable electron configurations.

• Group behavior is essential for understanding reactivity in chemical processes.