Atomic structure/radioactivity

• Name the three subatomic particles in an atom.

  Protons, neutrons and electrons.
• What are the masses of a proton, neutron and electron?

  Proton: 1

  Neutron: 1

  Electron: 0 (negligible)
• What are the charges of a proton, neutron and electron?

  Proton: +1

  Neutron: 0

  Electron: -1
• Why do atoms have no charge overall?

  Have the same amount of positive protons and negative electrons.
• Which particle do all atoms of the same element have the same number of?

  Protons.
• What does the atomic number tell us?

  Number of protons.
• what does the mass number tell us?

  Number of protons and neutrons.
• What is an isotope?

  Atoms with the same number of protons but different number of number of neutrons.
• Describe the early 'plum pudding' model of the atom.

  Ball of positive charge with negative electrons embedded in it.
• What two things did Rutherford's alpha scattering experiment show which disproved the plum pudding model?

  Most of the mass of an atom is concentrated in the nucleus.

  Nucleus is positively charged.
• What do some atoms emit radiation from their nucleus ?

  Because the nucleus is unstable.
• What is alpha radiation?

  2 protons, 2 neutrons.
• What is beta radiation?

  Electron.
• What is gamma radiation?

  EM wave.
• What type of radiation is the most penetrating?

  Gamma.
• What type of radiation is the most ionising?

  Alpha.
• Why is radiation dangerous?

  Damages cells. May cause cancer or even death.
• Which type of radiation is the most dangerous at close range?

  Alpha (as it is the most ionising).
• Which type of radiation is the most dangerous at long range?

  Gamma (as it is the most penetrating).