13.2.14

Nuclear Instability

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Nuclear Instability

Some isotopes of atoms are more stable than others. The unstable isotopes can decay radioactively.

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Stability

  • Above is a graph of the number of neutrons against the number of protons in an atom
  • There is a pattern where some atoms are more stable.
  • An unstable atom will decay to a more stable atom.
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Types of decay

  • Atoms usually decay through alpha or beta radiation untill they reach a stable point.
  • Any chain of alpha and beta radiation is possible to reach a stable point.
  • Alpha radiation reduces the atom by two neutrons and two protons.
  • Beta radiation reduced the atom by one neutron and increases by one proton.

Decay Equations

When an atom decays it may release radiation and a new atom is created. We can write equations for this decay.

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Types of radiation

  • Alpha radiation is made up of two protons and two neutrons.
    • The mass number will reduce by four and the atomic number by two.
  • Beta radiation changes a neutron into a proton and releases an electron.
    • The mass number will not change but the atomic number will increase by one.
  • Gamma radiation is a wave and will only change the energy of the atom, not the form
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Equations of decay

  • A decay equation shows the mass and atomic numbers for all of the atoms or radiation present.
  • Charge and mass must be conserved so we know that the sum of the mass number before and the sum after have to be the same.
  • We can work out what type of radiation is produced if we know the mass and atomic number before and after.
    • Remember radiation is a product, not a reactant. It should be after the arrow.

Jump to other topics

1Physical Quantities & Units

2Measurement Techniques

3Kinematics

4Dynamics

5Gravitational Fields

6Deformation of Solids

7Thermal Physics

8Oscillations

9Communication

10Electric Fields

11Current Electricity

12Magnetic Fields

13Modern Physics

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