Topic 2 - Atoms, elements and molecules

Cards (21)

  • Atoms on a picture look like single circles
  • Molecules of a compound on a picture look like two small circles stuck together or a small circle
  • Molecules of a mixture is just molecules but different kinds of molecules in the picture
  • Molecules of a compound look like a big ball and then two small circles
  • Periodic table: 118 elements
  • Everything is made up of atoms
  • Mixture: 2+ elements not joined together
  • Element: simple substances made of only one kind of atom
  • Compound: 1+ element joined together
  • Molecule: A group of atoms bonded together
  • Metals obtained from compounds are minerals
  • Metals have a high melting point, are malleable and ductile, shiny, good conductors of heat and electricity.
  • Copper, zinc and iron are metals
  • Non-metals: low melting point, brittle, not shiny, good insulators of heat and electricity.
  • Sulphur, oxygen, iodine and carbon are non-metals
  • Zinc + oxygen -->?
    Zinc oxide
  • Sodium + carbon -->?
    Sodium carbonate
  • Chemical reactions always form 1+ new substances
  • Physical reactions form no new substances
  • Heat is often needed to start a chemical reaction
  • Signs of a chemical reaction: colour change, gas being given off, an energy change and a solid forming in a liquid.