Periodic table & atomic structure

• The periodic table is organised into groups (columns) and periods (rows).
• Elements are arranged by increasing atomic number.
• Groups contain elements with similar properties, while periods contain elements that have the same number of energy levels.
• Group Number


  • 1
  • 7
  • 8/0
  • 13
• Group Name


  • Alkali Metals
  • Halogens
  • Noble gases
• Properties


  • Reactive metals
  • Reactive non-metals
  • Reactive non-metals
• Atom


  Has two main parts: a positively charged nucleus and negatively charged particles called electrons
• Nucleus


  • Made up of two different types of subatomic particles: protons and neutrons
  • Surrounded by one or more lightweight particles called electrons
  • Very dense
• Proton


  • Positively charged subatomic particle
  • Mass of 1 atomic mass unit (1 amu)
• Neutron


  • Neutral subatomic particle
  • Mass of 1 atomic mass unit (1 amu)
• Electron


  • Negatively charged particle
  • Lightweight
  • Arranged in electron shells (or orbitals)
• Atoms


  • Contain equal numbers of electrons and protons
  • Have no overall charge
  • Contain two differently charged particles
• Subatomic particles


  • Protons
  • Neutrons
  • Electrons
• Elements in the periodic table

  Arranged in increasing atomic number
• Atomic number


  Tells us how many protons the atom contains
• Mass number


  Total number of protons and neutrons the atom contains
• Mass of protons and neutrons are counted when measuring the mass of an atom
• Mass of electrons are not counted when measuring the mass of an atom
• Number of neutrons


  Can be found by subtracting the atomic number from the mass number
• Number of protons


  Equal to the number of electrons in an atom
• Symbol, atomic number and mass number of an element can be found on pages 4, 6 and 7 of the data booklet