Atoms

• What are the particles found in the nucleus of an atom?

  Protons and neutrons
• What is the charge of a proton?

  +1
• What is the charge of a neutron?

  0
• What is the charge of an electron?

  -1
• What is the relative mass of a proton?

  1
• What is the relative mass of a neutron?

  1
• What is the relative mass of an electron?

  0 (1/2000, ‘negligible‘)
• What is the overall charge of an atom?

  0
• Why do atoms have a neutral charge?


  Equal protons and electrons, cancelling out the charges
• What does the atomic number of an atom tell you?

  Number of protons or electrons (only if it is a neutral atom)
• What does the mass number tell you?

  Number of protons and neutrons
• How can you use the atomic number and mass number of a given atom, to work out how many neutrons it has?

  Number of neutrons = mass number - atomic number
• Is the mass number the biggest number on an atom symbol or smallest?

  Biggest. The atomic number is the smallest