How ‘Radioactivity is a nuclear phenomenon.’

A nuclear phenomenon is one in which there is some change occurring inside nucleus as against chemical reactions where only the loss, gain or sharing of electrons are involved. As radioactivity is exhibited by those atoms whose nucleus is unstable resulting in emission of particles or energy in the form of rays. Thus Radioactivity is a nuclear phenomenon. read less

Radioactivity must be a nuclear phenomenon for the following reasons: There are three kinds of radioactive decay particles and all of them carry the clue about their origin. Alpha Rays : Alpha radiation is made of alpha particles which are positively charged and are heavy. When examined these particle were found to be Helium-4 nucleus. The configuration of two protons and two neutrons seem to have exceptional stability and so when bigger nucleii disintegrate they seem to be disintegrating in such units. Clearly protons and neutrons are constituents of nucleus. Thus alpha radiation makes it obvious that they originate from the atomic nucleus. Beta Rays : Beta radiation is made of beta particles that are either positively (?+ decay) or negatively (?? decay) charged. When examined carefully they were found to be positrons, in the case of ?+ decay and electrons , in the case of ?+ decay. The electron could be from outside the nucleus but the clue for their nuclear origin comes from the change that happens to the nuclear charge after the beta decay. After a nucleus undergoes a ?? decay, emitting an electron, it is found that the atomic number of the nuclus goes up by one. This is a clear indication that the electron is the byproduct of some interaction involving the nucleons. Gamma Rays : Gamma radiation are made of particles that are charge neutral. When examined it was revealed to be extremely high energetic electromagnetic radiation with energies in the range of MeV . Electronic rearrangement can give photons in the energy range of few eV s. So the gamma rays cannot be due to electronic rearrangements. However the energy levels of the nucleons in atomic nuclei are in the range of MeV s. So they must be of nuclear origin.. U.K.AKSHAY read less

while conducting experiment on uranium salts, he found that uranium salts has a capability to blacken the photographic plate kept in a dark place wrapped through a paper Subsequent experiments showed that radioactivity is a nuclear phenomenon in which an unstable nucleus under goes a decay process referred as radioactive decay There are three types of radioactivity decays that occur in nature .These are ? decay ,? decay and ? decay. We now define radioactive decay as the process by which unstable atomic nucleus looses energy by emitting ionizing particles or radiations ( ?,? and ? rays) Radioactive decay of an atomic nucleus is a spontaneous process and can occur without any interaction of other particles outside the atom This process of radioactive decay is random and we can not predict whether a given radioactive atom will emit radiations at a particular instant of time or not Phenomenon of radioactivity is observed in heavy elements like uranium and unstable isotopes like carbon 14 2) Properties of radioactive decay Radioactive rays ionize the surrounding air and affect photographic plate Radioactive rays acts differently on different biological cells and tissues A beam of radioactive rays from a radium sample into three components in presence of strong magnetic or electric fields read less