Radioactivity is the spontaneous decay or disintegration of the nucleus of the atom of a radioactive element during which radiations ( α, β and γ-particles) and energyEnergy is the ability to do work. Energy exists in several forms such as heat, kinetic or mechanical energy, light, potential energy, and electrical energy. Units of Energy: The SI unit... More are emitted
Radioactive elements are elements that are capable of spontaneous decay with emission of radiation and energy. Examples of such elements are uranium, boron, thorium, radon, cobalt, radium.
Properties of Radioactive Radiations
α-particles | β-particles | γ-particles | ||
1. | effect of electric field | deflected towards the –ve plate | Deflected towards the +ve plate | Unaffected |
2. | Effect of magnetic field | Deflected toward the south pole | Deflected towards the north pole | Unaffected |
3. | Nature of charge | Positively charged | Negatively charged | Neutral |
4. | Mass | Massive (heavy) | Less massive | No mass |
5. | Momentum | High momentum | Low momentum | No momentum |
6. | Penetrating power | Low penetration power | High penetration power | Very high penetration power |
7. 8. | Nature of the atom Ionization power | Helium nucleus High ionization power | High energy electrons Low ionization power | Electromagnetic radiation of short wavelength No ionization |
Types of Radioactivity
There are two types of radioactivity namely natural radioactivity and artificial radioactivity.
Natural radioactivity is the splitting or breakdown of nuclei of elements on their own without any stimulation from man, during which α-particles, β -particles, γ-ray, or combination of any of these with accompanied energy.
Artificial radioactivity – this is achieved by bombarding ordinary materials with radioactive particles to give radioactive elements radiation and energy. E.g.
\( \scriptsize _{13} ^{27} \textrm {Al} + \; _{2} ^{4} \textrm {He} \rightarrow \; _{15} ^{30} \textrm {P} + \; _{0} ^{1} \textrm {n} \rightarrow \; _{14} ^{30} \textrm {S} + \; _{1} ^{0} \textrm {e} + energy\)When an aluminum is bombarded with helium or alpha particles, it gives rise to unstable phosphorus nuclei (radioactive phosphorus) which disintegrates further spontaneously into stable silicon atoms
Neutrons, protons and alpha particles are used as very effective bombarding particles for disintegrations of nuclei of elements.
Radioisotopes are isotopes made artificially by bombarding neutrons or proton or deuterons at elements
Radioactive elements are elements that spontaneously emit radiation from their nucleus e.g. radium, uranium, radon.
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