Structure

• What is the definition of atomic number?

  Total number of protons / electrons
• What is the definition of atomic mass?

  Total number of protons and neutrons
• What is the definition of an isotope?

  Another form of an element with a different number of neutrons and a different mass number
• What is the definition of an ion?

  An atom that has gained or lost electrons, giving it a negative or positive charge
• What is the definition of periodicity?

  A repeating trend in the periodic table
• What is the relative mass of an electron?

  0.0005
• What was John Dalton’s model of an atom called and what did it describe the atoms as?

  Solid sphere model and it described atoms as invisible spheres, he came up with this in 1803
• What was J.J Thomson’s model of an atom called and what did it describe the atoms as?

  Plum pudding model, described atoms as a positively charged sphere with negatively charged electrons embedded in it, he came up with it in 1897
• What was Ernest Rutherford’s model of an atom called and what did it describe atoms as?

  Rutherford model Described atoms as mostly empty space with a dense, positively charged nucleus, he came up with it in 1909
• How did Rutherford prove his model?

  Through the gold foil experiment where positively charged alpha particles where shot at a piece of gold foil
• What were the results of the gold foil experiment?

  Most particles passed straight through, some were reflected and some completely deflected
• What did the gold foil experiment prove and how?

  The atom was mostly empty space as most particles passed through, there was a positive dense mass in the centre as some particles were deflected completely and there were negative electrons surrounding the atom as some were reflected
• What was Neils bohr model of an atom called and what did it describe the atoms as?

  Planetary model

  He proposed that electrons had different energy shells that surrounded the central nucleus
• What was the experimental proof for the planetary model?

  When EM radiation is absorbed, electrons move between shells. They emit this radiation when electrons move down to lower energy shells