Question

a) Three types of radioactive decay occur in nature. Briefly describe them.
b) State the law of radioactive decay.

Answer 1

The spontaneous decay of the atomic nucleus resulting in the release of energy and matter from the nucleus is the radioactive decay. There are unstable radioisotopes nuclei that do not have ample binding energy to hold the nucleus intact.

Complete answer:
(a) Three types of radioactive decay exist in nature:
Alpha decay is a radioactive process in which two neutrons and two protons are expelled from the nucleus of a radioactive atom. The particle is identical to the nucleus of the helium atom. They have a positive charge of two since the alpha particles contain two protons. Beta-decay is a radioactive process in which, along with a peculiar particle called an antineutrino, an electron is released from the nucleus of a radioactive atom. Neutrino is an almost massless particle that removes some energy from the decay process. As this electron is from the nucleus of the atom, to differentiate it from the electrons orbiting the atom, it is called a beta particle. Gamma decay is a form of radioactivity where an unstable atomic nucleus dissipates excess energy via a random electromagnetic process. Gamma rays are irradiated to the most common form of decline known as gamma emissions (photons or electromagnetic energy packs with an extremely short wavelength).
b) The radioactive decay law:
The number of nuclei decreasing over a given period of time is directly proportional to the total number of nuclei initially present. And the sum of decay in nuclei is directly proportional to the time period. We get a mix of the two:
$\dfrac{\vartriangle N}{N}=-\lambda\vartriangle t$
Where N = the number of nuclei initially present, $\vartriangle N$ = The number of nucleus decay and SIN = Decay constant.
We get after integrating,
$\dfrac{\vartriangle N}{N0}={{e}^{-\lambda t}}$

Note: If the nucleus of an atom is unstable and spontaneously releases energy in the form of radiation, nuclear decay occurs. As a result, the nucleus transitions to the nucleus of one or more other elements. These daughter nuclei have a lower mass and are more stable than the parent nucleus (lower energy).