Topic 4 - Atomic Structure

• How did John Dalton describe atoms?

  as solid spheres and different spheres made up different elements
• What model did J.J Thompson create?

  Plum pudding model
• When was the plum pudding model invented?

  1897
• What was the plum pudding theory?

  spheres of positive charge with tiny negative electrons stuck in them like plums in a plum pudding
• What model did Ernest Rutherford create?

  Nuclear model
• When was the nuclear model created?

  1909
• What was the nuclear model?

  a positively charged nucleus surrounded by negative electrons.
• What did Niels Bohr discover?

  Discovered electrons are arranged according to energy levels = low energy levels close to nucleus
• When did Niels Bohr make his discovery?

  1913
• What did James Chadwick discover?

  He discovered the neutron
• What does a radioactive material consist of?

  unstable isotopes that can decay
• what is an alpha particle made of?

  2 protons and 2 neutrons
• what is a beta particle made of?

  an electron
• what is a gamma particle made of?

  electromagnetic waves
• what charge does a gamma particle have

  no charge
• what charge does an alpha particle have

  +2
• what charge does a beta particle have?

  negative 1
• define activity


  Rate at which decay occurs
• what are the units of activity?

  Becquerels (Bq)