C1 retrieval

• What is an atom?

  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?

  Sphere or 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 - this showed that an atoms mass and positive charge must be concentrated in one small space (nucleus)
• Describe the nuclear model of the atom

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

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

  uncharged particle called the neutron
• Where are protons and neutrons?

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

  Proton: 1

  Neutron: 1

  Electron: 0 (very small)
• 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?

  The atomic number on periodic table
• How can you calculate the number of neutrons in an atom?

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

  Equal numbers of positive protons and negative electrons
• How many electrons can you place in the first, second and third shells?

  1st = up to 2

  2nd and 3rd = up to 8
• What is an element?

  Substance made of one type of atom
• What is a compound?

  Substance made of more than one type of atom chemically combined together
• What are isotopes?


  Atoms of the same element, with same number of protons but different number of neutrons
• The four physical processes that can be used to separate mixtures

  Filtration, crystallisation, distillation, fractional distillation, chromatography
• What is a mixture?

  Two or more substances not chemically combined
• What is relative mass?

  The average mass of all the atoms of an element