Have you ever wondered where the elements originally came from?
I think it is time for a little stardust and some Brain Cox! This video clip sets the scene for understanding the importance of fusion reactions.
At the extremely high temperatures in the ‘heart’ of stars the atomic nuclei have such enormous speeds and kinetic energies that on collision they can fuse together, releasing enormous amounts of energy.
The extremely high energy is needed to overcome the natural and massive repulsion of the two positive nuclei involved.
The smallest atom is hydrogen, this is converted to helium and gradually all the other elements up to uranium must have been formed in stars like the Sun.
For example, a nucleus of hydrogen-1 and deuterium collide to form a nucleus of helium-3 and gamma radiation is released:
In addition to gamma radiation, protons, positrons, electrons or neutrons may be emitted:
Practice questions
Write an equation for each of the following nuclear fusion reactions:
1. Two deuterium nuclei fuse to form one nucleus of tritium and one hydrogen nucleus
2. Two deuterium nuclei fuse to form one helium-3 nucleus and a neutron
3. One nucleus of tritium fuses with one nucleus of deuterium to form one nucleus of helium-4 and a neutron
In the next questions, you have to work out if any other particles are formed in the fusion reaction for yourself:
4. One carbon-13 nucleus fuses with one helium-4 nucleus to form a nucleus of oxygen-16
5. One plutonium-239 nucleus fuses with two neutrons to form one americium-241
6. One nucleus of californium-252 fuses with one nucleus of boron-11 to form a nucleus of lawrencium-257
Answers
