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Explore nuclear reactions including fission, fusion, and alpha & beta emissions. Follow an alpha decay series to lead formation. Start plotting elements and predicting decay steps for an engaging learning experience!
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In chemical reactions, electrons in atoms are responsible for bonds forming and being destroyed. The identity of the atoms involved does not change
This is not true for nuclear processes because; These reactions involve the protons and neutrons in the nucleus
There are two types of nuclear reaction Fission and Fusion Reactions
Fission Reactions • Involve a nucleus collapsing to form a smaller nucleus • Usually involve atoms with large nucleii such as the Lathanides and Actinides • They produce , and emissions.
Fusion Reactions • These involve nucleii joining together to make larger ones. • These type of reactions are what go on inside stars and provide the energy which make them shine.
The particle • Consists of 2 protons and 2 neutrons • Is emitted from a nucleus during radio active decay • Is the most destructive radiation because it ionises atoms it bumps into
The particle • The particle is the same as a Helium atom with the electrons removed. • It is often written as He 42 in nuclear equations
An decay reaction The Uranium atom U23892 decays by particle emission 238 4 234 U He ? + 2 92 90 What is represented by ?
An decay reaction The Uranium atom U23892 decays by particle emission 238 4 234 U He Th + 2 92 90 Th is thorium – we can work it out by using the periodic table and looking up the atom with atomic number 90. The mass number does not matter – it is simply an isotope of Th.
More decay reactions The Thorium atom Th22790 decays by particle emission 227 Th Complete the equation 90
More decay reactions 227 4 223 Th He Ra + 2 90 88
More decay reactions The Actinium atom Ac22589 decays by 3 particle emissions 225 Ac Complete the equation 89
More decay reactions 225 4 213 Ac 3He Bi + 2 89 83
Particle emissions Particles are electrons but they do not come from the electron shells which surround the nucleus – they come from the nucleus itself. The electron is emitted when a neutron becomes a proton. N10 p110-1
Particle emissions The effect of Particle emission is to increase the proton count by 1 whilst leaving the overall mass unchanged. 231 0 Th ? + -1 90 What is ?
Particle emissions The effect of Particle emission is to increase the proton count by 1 whilst leaving the overall mass unchanged. 231 231 0 Th Pa + -1 90 91 Notice how particle emission raises the atomic number by 1
Decay Series When a radioactive nucleus such as U23892 decays it often produces another radioactive isotope which goes on to decay further. We are going to construct a decay series on graph paper for the element U23892 to show how it eventually forms a stable isotope of lead Pb20682
GET A PIECE OF GRAPH PAPER • Draw a vertical axis representing atomic mass. It will need to run from 200 to 240 • Draw a horizontal axis representing atomic number. It will need to run from 78 to 93. • Position the isotope U23892 on your graph and mark it clearly.
240 * U23892 Mass 200 78 93 Number
Plotting an decay • The nucleus gives off an alpha particle first to form a new nucleus • Work out what the new nucleus is • Find the nucleus on your graph and add it in • Join the points with an arrow
240 * U23892 Th23490 * Mass 200 78 93 Number
Plotting a beta emission • The Thorium next loses a Beta particle • Work out what would be formed • Add the nucleus onto your chart
240 * U23892 Th23490 * * Pa23491 Mass 200 78 93 Number
Building up the decay series Continue to build up the series using the following emissions. Each alpha emission is shown as a diagonal to the left and each beta emission is a horizontal line to the right. If you are successful you should end up with Pb20682 Good Luck !
8. 9. 10. 11. 12. 13. 14. Emission sequence (including the first two example emissions)