C2

• States of matter


  The three forms in which a substance can exist (solid, liquid, and gas)
• Particle model


  The scientific theory used to explain the properties of solids, liquids and gases. It involves the arrangement and movement of the particles in a substance.
• Particle


  A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules.
• Energy


  The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow.
• Comparison of the same substance in three different states

  • Solid
  • Liquid
  • Gas
• A single particle does not have the properties of the material it is part of. The properties of a substance are the properties of a huge number of particles together.
• Solids


  • Have a fixed shape and cannot flow, because their particles cannot move from place to place
  • Cannot be compressed (squashed), because their particles are close together and have no space to move into
• Liquids


  • Flow and take the shape of their container, because their particles can move around each other
  • Cannot be compressed, because their particles are close together and have no space to move into
• Gases


  • Flow and completely fill their container, because their particles can move quickly in all directions
  • Can be compressed, because their particles are far apart and have space to move into
• Solid


  One of the three states of matter, where particles are closely packed and have a fixed shape and volume
• Liquid


  One of the three states of matter, where particles are close together but can move past each other, having a fixed volume but no fixed shape
• Gas


  One of the three states of matter, where particles are far apart and can move freely, having no fixed shape or volume
• Sublimation


  When a solid turns straight into a gas on heating, without becoming a liquid first - or when a gas turns straight into a solid, without becoming a liquid
• Solid carbon dioxide ('dry ice') can sublime
• Energy


  The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J).
• Particle


  A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules.
• Bond


  The chemical link that holds molecules together.
• Melting


  The process that occurs when a solid turns into a liquid when it is heated.
• Evaporation


  The process in which a liquid changes state and turns into a gas.
• Boiling


  Changing from the liquid to the gas state, in which bubbles of gas form throughout the liquid.
• Melting point


  The temperature at which a solid changes into a liquid as it is heated.
• Boiling point


  The temperature at which a substance rapidly changes from a liquid to a gas.
• Evaporation can take place below the boiling point of a substance
• Condensing


  Energy is transferred from a substance to the surroundings when a substance condenses
• Freezing


  Energy is transferred from a substance to the surroundings when a substance freezes
• Ionic compound


  Made up of charged particles, called ions, with a giant lattice structure and strong electrostatic forces of attraction
• Ionic compounds


  • Formed when a metal reacts with a non-metal by transferring electrons
  • Oppositely charged ions are strongly attracted to each other, forming ionic bonds
• Forming ionic bonds


  1. Positive and negative ions form

  2. Metal atoms lose electrons

  3. Non-metal atoms gain electrons

  4. Oppositely charged ions are strongly attracted, forming ionic bonds
• Dot and cross diagrams model the transfer of electrons from metal atoms to non-metal atoms
• The outer electron from a metal atom transfers to the outer shell of a non-metal atom
• Ionic bonding forms between two atoms when an electron is transferred from one atom to the other, forming a positive-negative ion pair
• Ionic compounds have a giant lattice structure with strong electrostatic forces of attraction
• Ionic compounds are made up of charged particles called ions
• Ionic compound


  Made up of charged particles, called ions
• Ionic compound


  • Has a giant lattice structure with strong electrostatic forces of attraction
• Ionic lattice


  The regular, repeating arrangement of ions in an ionic substance
• Solid ionic compounds form crystals with regular shapes
• Ionic bonding


  The strong electrostatic forces of attraction between the oppositely charged ions in the lattice
• The forces of attraction between ions in the lattice act in all directions
• Ionic compound


  Made up of charged particles, called ions. Has a giant lattice structure with strong electrostatic forces of attraction.