Chemistry

• Atom


  Something that can't be broken down or split into its constituents or smaller bits by chemical means
• Compound

  Two or more types of atoms chemically bonded together
• Mixture


  Different types of atoms or compounds not chemically bonded together
• Chromatography

  Filter paper with a dot of the mixture about a centimeter above the water line, the filter paper is dipped in water, the water gets drawn up the paper due to capillary action and drags particles of the mixture with it, the particles that end up the highest on the paper are the lighter particles
• RF value


  Retention factor, calculated by doing how far the solute has gone up the paper divided by how far the solvent has gone
• Filtration


  Removes insoluble particles like sand from water, using filter paper in a funnel
• Distillation


  Separates a solid from a solvent like salt from water, by heating the mixture or solution, the water evaporates and is then re-condensed using a condenser tube
• Nucleus


  Contains neutrons and protons in the middle of an atom
• Electrons


  Orbit around the outside of the nucleus
• Protons


  Have a charge of +1
• Electrons


  Have a charge of -1
• Neutrons


  Have no charge
• Atoms have to have the same number of protons as electrons so they are neutral
• Ion


  An atom that has lost or gained electrons, resulting in a positive or negative charge
• Columns/Groups in the periodic table

  • 1 2 (gap) 3 4 5 6 7 8 or 0
• Column/Group


  Tells you how many electrons are in the outer shell
• Period


  Tells you how many shells of electrons an element has
• Types of elements


  • Metals (to the left of the staircase)
  • Nonmetals (to the right of the staircase)
• Metals


  Electron donators, lose electrons when they bond
• Nonmetals


  Electron acceptors
• Groups in the periodic table

  • Group 1 (Alkali metals)
  • Group 7 (Halogens)
  • Group 8 or 0 (Noble gases)
• Atomic number


  Number of protons in the nucleus
• Mass number


  Number of protons plus neutrons in the nucleus
• Electron shell filling

  2 8 8 2
• We only really care about the first 20 elements, up to calcium, because it gets messy after that
• Chlorine


  Atomic number 17, has 17 protons and 17 electrons, with 7 electrons in the outer shell
• Ionic bonding


  Metals bond to nonmetals by donating electrons, forming positive and negative ions
• Ionic compound


  • Magnesium chloride (MgCl2)
• Dot and cross diagram for ionic bonding


  Metal has an empty outer shell, nonmetal has crosses for electrons and dots for donated electrons from metal
• Ionic compounds


  • Have high melting and boiling points, are soluble in water, can conduct electricity when molten or in solution
• Covalent bonding


  Nonmetals bond to other nonmetals by sharing electrons to achieve a full outer shell
• Simple covalent compound


  • Methane (CH4)
• Dot and cross diagram for covalent bonding

  Draw the outer shells and show the shared electron pairs in the bonds
• Covalent compounds


  • Carbon dioxide (CO2) - has double covalent bonds
• Giant covalent structures


  Huge molecules with repeating covalent bonds, e.g. diamond, graphite, fullerenes, nanotubes
• Metallic bonding


  Atoms form a lattice with delocalized electrons surrounding the positive ions
• Polymer


  Long chain formed by joining many individual monomer molecules together
• Polymer


  • Polyethylene
• To make a polymer, high pressure and a catalyst are needed to force the monomers together
• First put the elements in weight order, didn't have a table

  John Dalton