Radioactivity

There are certain elements which emit some invisible rays (α, β, γ) by the process of self-disintegration. These elements have excess neutrons in their nucleus. By the process of nuclear disintegration into smaller fragments they emit invisible radiations. These atoms are called radioactive elements and the invisible rays emancipating from these elements are called radioactive rays.

All elements which lie in the range of atomic numbers 83 to105 are radioactive elements. Out of this atomic numbers 83 to 92 are natural radioactive elements while 93 to 105 are artificial. The radiations emitted by these elements are of three types:
α rays- These are positively charged and are equivalent to He⁺⁺  ions                
β rays- These are negatively charged electrons
γ rays- These are electrically neutral

The nuclei of radioactive elements are unstable and disintegrate by ejecting an α particle or a β particle. By ejection of α or β particles, new atoms are formed and if these atoms also have unstable nuclei then further emission also takes place, until a stable nuclei is found and a series of radioactive elements are obtained called radioactive series. There are four radioactive series-
i)Uranium series
ii)Thorium series
iii)Actinium series
iv)Neptunium series


I will discuss more about these series in my next post.