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• Atom


  The smallest part of an element that can exist
• Chemical symbol


  Representation of atoms of an element, starting with a capital letter
• Element


  A substance made up of only one type of atom
• The periodic table contains over a hundred different elements, each with unique properties
• Compound


  Contains two or more different elements chemically combined in fixed proportions
• Compounds have different properties from the elements that make them
• Compounds can only be separated into elements by chemical reactions, not by physical processes like filtration or distillation
• Chemical reaction


  Involves the formation of one or more new substances and often leads to an energy change
• Symbol equation

  Represents chemical reactions with chemical names for each substance
• Balancing a symbol equation

  Ensuring the same number of each type of atom on both sides of the equation
• Atom


  Made up of protons, neutrons, and electrons
• Proton


  Positively charged and found in the central nucleus of the atom
• Neutron


  Neutral and also found in the nucleus
• Electron


  Negatively charged and found in shells orbiting the nucleus
• Proton


  Relative charge is +1
• Neutron


  Relative charge is 0
• Electron


  Relative charge is -
• Proton and neutron


  Relative mass of 1
• Electron


  Tiny relative mass of approximately 1/1836
• Atoms of different elements have different numbers of protons, giving them different properties
• All atoms of a particular element have the same number of protons
• Almost all of the mass of an atom is found within the nucleus
• Isotopes


  Atoms of the same element with the same number of protons but different numbers of neutrons
• Ion


  A charged particle formed when an atom or a molecule gains or loses electrons
• Cation


  An ion formed when an atom loses electrons, becoming more positive
• Anion


  An ion formed when an atom gains electrons, becoming more negative
• Electron shells


  Electrons are found within shells or energy levels
• The first shell can hold up to 2 electrons, the second shell up to 8, and the third shell up to 8
• Mass number


  Represents the sum of protons and neutrons
• Atomic number


  Represents the number of protons
• Atoms have no overall charge, and the number of protons must be equal to the number of electrons
• Calculating protons, neutrons, and electrons for an atom

  1. Protons = Atomic number

  2. Neutrons = Mass number - Protons

  3. Electrons = Protons
• Calculating protons, neutrons, and electrons for an ion

  1. Protons = Atomic number

  2. Neutrons = Mass number - Protons

  3. Electrons = Protons + charge (for cations) or Protons - charge (for anions)
• Relative atomic mass


  The average mass of all the atoms of an element when compared to 1/12 of the mass of a carbon-12 atom
• This definition explains why the relative atomic mass of some elements on the periodic table are not whole numbers, as they are averages of several different isotopes
• Mixture separation techniques


  • Filtration
  • Crystallization
  • Simple distillation
  • Fractional distillation
  • Chromatography
• Filtration


  Used to separate mixtures of insoluble solids and liquids
• Simple distillation


  Separates a solvent from a solution and is used to keep the liquid
• Fractional distillation


  Separates two or more liquids with different boiling points
• Crystallization


  Separates a dissolved solid (solute) from a solution