Atoms, Elements, Compounds, and Mixtures

• Matter describes anything that has mass and takes space
• Matter is made up of ATOMS
• Atoms are the smallest unit of matter that have the properties of a chemical element. It is so small that you can't see them with your eyes or even through a standard laboratory microscope
• Atoms are made up of even smaller (subatomic) particles
• A CHARGE is a physical property. It allows the particles to move through (or remain still in) in an electromagnetic field
• Electrons: particles with negative (-) charge
• Protons: particles with positive (+) charge
• Neutrons: particles have no charge, they are neutral.
• Protons and Neutrons are located in the NUCLEUS, or center of the atom. Because protons have a positive (+) charge and neutrons have no charge, the nucleus has an overall positive charge
• Determine the subatomic particles

  A) Proton

  B) Neutron

  C) Electrons

  
• Electrons, protons, and neutrons are actually not the smallest known particles of matter. There are smaller particles: leptons, muons, tau particles, and quarks
• A NEUTRAL ATOM will have the same number of protons and electrons. Because the number of electrons is the same number of protons, the atom has no overall change
• A POSITIVE ATOM will have more protons than electrons
• A NEGATIVE ATOM will have more electrons than protons
• atoms are usually classified as elements or pure substance
• A PURE SUBSTANCE is made up of only one type of atom or one type of molecule. It can either be an element or compound. Oxygen, hydrogen, and sodium are examples of this
• Molecule - two or more atoms joining together chemically
• Compound - a molecule that at least contains two different elements that are chemically combined in a fixed ratio
• Chemical substance - something that can't be separated into its components by physical methods
• Mixture - made out of two or more different substances that are combined
• Heterogenous - mixtures contain substances that are not in uniform position. The parts in the mixture can be separated by physical means
• Homogenous - mixtures are the same throughout and cannot be separated by physical means
• Filtration - separates an insoluble solid from a liquid or solution.

  
• Chromatography - a separation process that requires two different phases of matter. It can be used to separate two solids that are mixed to create the same liquid. A thin layer of silica is placed onto a plate. The plate is then placed into a solvent that slowly moves up the plate, separating the parts of the liquid. It is used to test whether a liquid is a substance or a mixture. It does not separate the entire sample

  
• Evaporation - separates a soluble solid from a liquid, usually water. The solution of the solid and liquid is boiled until the liquid evaporates into thin air.

  
• Extraction - the act of isolating one compound from another. The mixture is brought into contact with a solution in which the substance wanted is soluble, but the other substances present are insoluble

  
• Distillation - the action of purifying a liquid by the process of heating and cooling. It can be used to separate two liquids with different boiling points by heating them to evaporate one of them and then cooling it to condense it while the other remains a liquid. This method is mostly used to purify liquids