Only through such radioactive decays or nuclear reactions can transmutation, the age-old dream of the alchemists, actually occur.
The mass number, He is two, and therefore the atomic number of the nucleus, the number of protons, is reduced by two.
Once again, Einstein's equation, E=mc, explains that the mass that is lost it converted into energy carried away by the fusion products.
Even though fusion n is an energetically favorable reaction for light nuclei, it does not occur under standard conditions here on Earth because of the large energy investment that is required.
A given element can have many different isotopes, which differ from one another by the number of neutrons contained in the nuclei.
In a neutral atom, the number of electrons orbiting the nucleus equals the number of protons in the nucleus.
Beta particles, however, are emitted with a continuous range of energies from zero up to the maximum allowed for by the particular isotope.Materials that emit this kind of radiation are said to be radioactive and to undergo radioactive decay.In 1899, Ernest Rutherford discovered that uranium compounds produce three different kinds of radiation.An example of a fusion reaction important in thermonuclear weapons and in future nuclear reactors is the reaction between two different hydrogen isotopes to form an isotope of helium: This reaction liberates an amount of energy more than a million times greater than one gets from a typical chemical reaction.Such a large amount of energy is released in fusion reactions because when two light nuclei fuse, the sum of the masses of the product nuclei is less than the sum of the masses of the initial fusing nuclei.