atomic structure of the atom

• In the plum pudding model what are the dots or Xs in the centre called


  electons
• The nuclear model shows us that atoms have a small positively charged nucleus with negatively charged electrons orbiting around it.
• the nuclear model was developed by Ernest Rutherford
• The particle with a positive charge is a proton
• The particle with the smallest mass is a electron
• Neutrons have no charge
• The number of neutrons can vary within an element to form different isotopes
• when an electron is removed from an atom, the name given to the atom is...


  an ionan ion
• Atoms of the same element will always have the same number of protons, so they all have the same chemical properties
• What method did Rutherford use to provide evidence for the structure of the atom?

  Scattering of alpha particles
• What is the purpose of the vacuum chamber in Rutherford's experiment?


  To prevent air molecules from causing scattering
• What are the reasons for having a vacuum in the chamber during Rutherford's experiment?


  • Air molecules would cause scattering
  • To prevent the α-particles being absorbed or scattered
• Why is it important to prevent the α-particles from being absorbed or scattered?


  To ensure accurate results in the experiment
• What could happen if air molecules were present in the vacuum chamber?


  They would cause scattering of the α-particles
• What is the role of the gold foil in Rutherford's experiment?


  It serves as the target for the α-particles
• Electrons orbit the nucleus at different distances
• The different orbit distance are called energy levels
• The further away from the nucleus the greater the energy
• When an electron absorbs energy, it moves closer to the nucleus (to a lower energy level)
• When an electron loses energy, it moves further away from the nucleus (to a higher energy level)
• An electron can only move between two specific energy levels