Elements and Atoms

• Atoms

  Every known substance in the universe is made of these. They are the basic building blocks of everything. Only about 100 types are known to exist. The smallest part of an element
• What are atoms made of?


  They made of three different sub-atomic particles: protons, neutrons and electrons.
• How to calculate the mass of an atom 


  Mass of an atom = number of protons + number of neutrons
• A pure substance is made of only one type of atom.
• The smallest part of a substance that still retains the same chemical properties is the atom.
• Molecule


  A group of atoms bonded together. e.g. H2O
• Compound


  Substance made from at least 2 different atoms which are chemically bonded and in a fixed ratio. Properties of these are very different to the atoms or elements that make them up, and the atoms are bound very tightly.
• Element


  Pure substance made from one type of atom. Each of these has unique properties
• Molecule


  A group of atoms bonded together. Two non metals. e.g. H20.
• Atomic mass = protons + neutrons
• Neutrons = mass - protons
• Protons


  Have a positive charge. Join together with neutrons to create the nucleus. The number of these indicates the element.
• Neutrons


  One of the three parts of an atom. They have a neutral charge, there can be any number of these in an atom, but extreme numbers will result in the atom falling apart. Make up the nucleus.
• Electrons


  One of the three particles that make up an atom. With a negative charge, they orbit around the nucleus. Electricity makes these jump from atom to atom.
• Metallic Elements

  Generally shiny, solid at room temperature, good conductors of heat and electricity, malleable and ductile.
• Non-Metallic Elements

  Tend to be dull, do not conduct heat or electricity and are brittle.
• Lattices

  Large grid-like structures of atoms
• Metallic Lattices

  Metallic elements are formed instead of being molecules. This makes metals strong and solid at room temperature thus can slide and move without breaking.
• Non-Metallic Lattices

  Carbon forms crystal lattices to make graphite and diamond. The atoms are bound tightly and in a fixed postion.
• Ion

  An atom that has lost or gained electrons. If you lose an electron, it becomes positive. If you gain an electron, it becomes negative.
• There is the same number of protons as electrons
• Compound Lattices

  These can form crystal lattices. The atoms are bound very tightly to each other so they are hard or solid at room temperature
• Mixture

  Can be made up of at least two elements, compounds or a combination however not in a fixed ratio or chemically bonded.
• Gaseous Mixture

  Gases can be mixed easily due to their weak bond between atom. Examples of gas mixtures is the ash in smoke and water droplets in fog
• Liquid Mixture


  Liquids that mix are miscible, liquids that don't mix are immiscible. Gases and solids can mix in liquids to form a solution.
• Alloys


  A mixture of metal with other metals or non-metals. They have very different properties to pure metal.
• There is an equal amount of protons and electrons in a stable atom.
• Gases are compressible because their particles are farther apart due to lower forces of attraction and high kinetic energy. However, once a gas is compressed to a certain point it will turn to liquid.
• Higher kinetic energy on atoms overcomes the force of attraction. Once it is completely overcome, the substance changes state.