An Unstable Nucleus
Nuclear reactions deal with changes in the nucleus of the atom and occur if the nucleus is unstable. The strong force, which comes from the neutrons, holds the nucleus together. More protons need more neutrons to bind the nucleus. As atomic number increases, the nucleus gets larger. When this happens, electrostatic repulsions between the protons weaken. The strong force is about 100X as strong as the electrostatic repulsions and it operates over short distances. After the nucleus reaches a certain size, the strong force is not able to hold it together. Adding extra neutrons increases the space between the protons. This, in turn, decreases the repulsions. but if there are too many neutrons, then the nucleus is once again out of balance and starts to decay.
The neutron-to-proton ratio in a atom determines if the nucleus is stable. The nucleus is deemed unstable if the N:P ratio is less than 1:1 or greater than 1.5:1.
The neutron-to-proton ratio in a atom determines if the nucleus is stable. The nucleus is deemed unstable if the N:P ratio is less than 1:1 or greater than 1.5:1.
Radioactive Decay
Radioactive Decay – A complex atom becomes simpler and simpler, or changes into another element. This process is called transmutation.
Out of 350 isotopes, ~70 are radioactive. Most are above atomic number 83.
In general:
Alpha decay
An alpha particle is emitted from nucleus of atom. An alpha particle is equivalent to a helium nucleus. It can barely pass through a sheet of paper, and is deflected as a positive particle in a magnetic field.
Radium-226 undergoes alpha emission. It loses 2 protons and 2 neutrons to become Radon-222.
Beta decay
A beta particle is emitted from the nucleus of atom. A beta particle is equivalent to an electron. Beta particles can pass through really thin aluminum sheets and are deflected as negative particles in a magnetic field.
Lead-210 undergoes beta decay to become bismuth-210.
Gamma emission
Causes no change in mass, equivalent to energy. Gamma particles are extremely dangerous and can pass through lead.
Out of 350 isotopes, ~70 are radioactive. Most are above atomic number 83.
In general:
Alpha decay
An alpha particle is emitted from nucleus of atom. An alpha particle is equivalent to a helium nucleus. It can barely pass through a sheet of paper, and is deflected as a positive particle in a magnetic field.
Radium-226 undergoes alpha emission. It loses 2 protons and 2 neutrons to become Radon-222.
Beta decay
A beta particle is emitted from the nucleus of atom. A beta particle is equivalent to an electron. Beta particles can pass through really thin aluminum sheets and are deflected as negative particles in a magnetic field.
Lead-210 undergoes beta decay to become bismuth-210.
Gamma emission
Causes no change in mass, equivalent to energy. Gamma particles are extremely dangerous and can pass through lead.