electronic structure + balancing equations

• Compounds


  Substances formed of two or more elements in fixed proportions
• Compounds


  • Elements within a compound are held together by chemical bonds
  • Can be represented by chemical formulas using the symbols of the atoms which they were formed
• Chemical Reaction


  1. Reactants (starting products)

  2. Bonds are broken within the reactants

  3. Bonds are formed to produce the products
• Chemical Reaction


  • Magnesium + Hydrochloric Acid → Magnesium Chloride + Hydrogen
• Chemical reactions can be described in words or abbreviated using the elements and compounds symbols and formulae
• Balancing Equations


  The number of atoms of x should be the same on both sides of the equations
• Periodic Table


  • The period (row) which the element is in dictates its number of shells
  • The group (column) which the element is in dictates the number of electron in the outer most (highest energy) shell
• Electron Structure


  • Electrons orbit the nucleus in shells
  • The shell closest to the nucleus is occupied first as it is the lowest energy level shell
  • The first shell can hold up to 2 electrons
  • Subsequent shells can hold 8 electrons