C1 Atomic structure

• What is an atom?

  The smallest part of an element that can exist
• What is Dalton's model of the atom?

  Atoms as solid spheres that could not be divided into smaller parts
• What is the plum pudding model of the atom?


  A sphere of positive charge with negative electrons embedded in it
• What did scientists discover in the alpha scattering experiment?

  Some alpha particles were deflected by the gold foil, indicating a concentrated nucleus
• Describe the nuclear model of the atom.

  A dense nucleus with electrons orbiting it
• What did Niels Bohr discover?

  Electrons orbit in fixed energy levels (shells)
• What did James Chadwick discover?

  The uncharged particle called the neutron
• Where are protons and neutrons located in an atom?

  In the nucleus
• What is the relative mass of each sub-atomic particle?

  Proton: 1, Neutron: 1, Electron: very small (considered as 0)
• What is the relative charge of each sub-atomic particle?

  Proton: +1, Neutron: 0, Electron: -1
• How can you find out the number of protons in an atom?

  By looking at the atomic number on the Periodic Table
• How can you calculate the number of neutrons in an atom?

  Mass number - atomic number
• Why do atoms have no overall charge?

  Because they have equal numbers of positive protons and negative electrons
• How many electrons would you place in the first, second, and third shells?

  Up to 2 in the first shell and up to 8 in the second and third shells
• What is an element?

  A substance made of one type of atom
• What is a compound?

  A substance made of more than one type of atom chemically joined together
• What is a mixture?

  A combination of two or more substances not chemically combined
• What are isotopes?

  Atoms of the same element with different numbers of neutrons
• What are the four physical processes that can be used to separate mixtures?

  Filtration, crystallisation, distillation, fractional distillation, chromatography
• What is relative mass?

  The average mass of all the atoms of an element
• What is the process of drawing atoms and their electron configuration?

  • Electrons are placed in fixed shells
  • Up to 2 electrons in the first shell
  • Up to 8 electrons in the second and third shells
  • Fill each shell before moving to the next one