1c - atomic structure 1d - periodic table

• Atom


  The smallest piece of an element that can still be recognised as that element
• Compound


  Two or more atoms (same/different) that are chemically joined together
• Subatomic particles


  • Protons
  • Neutrons
  • Electrons
• The atom is made up of three main subatomic particles
• Atomic number


  Represents the number of protons in the atom
• Mass number


  Represents the sum of the number of protons and the number of neutrons in the nucleus
• Isotopes


  Atoms of the same element with the same number of protons but different number of neutrons
• Relative atomic mass (A)


  The weighted mean mass of an atom (of an element) relative to the mass of a carbon-12 atom
• Everything in chemistry is about electrons
• Periodic Table


  • Elements are ordered by their atomic number (ascending)

  Groups (columns) represent the number of outer shell electrons

  Periods (rows) represent the number of shells around the nucleus
• Groups in the Periodic Table

  • G1: Alkali metals

  G7: Halogens

  G8: Noble Gases
• The maximum number of electrons that can be in each shell is 2, 8, 8
• Electronic configuration


  The arrangement of electrons in the shells/energy levels of an atom
• Noble gases have a full outer shell of electrons
• Group 0 elements do not react readily because they have a full outer shell of electrons
• Most elements on the Periodic Table are metals
• Special elements on the Periodic Table

  • Mercury and bromine are the only liquid elements

  Alkali metals (Group 1)

  Halogens (Group 7)

  Noble gases (Group 8/0)