Radioactivity is the spontaneous disintegration of the nucleus of an atom of an element. Radioactivity involves nucleus reactions. A chemical reaction involves the movement of an element in its nucleus, and the force holding the nucleus becomes weaker. Such an atom becomes unstable, it may break up on its own accord with the emission of energy.
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The first scientist to observe spontaneous emission of radiation by uranium salt was Becquerel in 1896. Pierre and Marie Currie also isolated two new radioactive elements -1.polonium 2. radium
Radioactive elements are isotopes of elements having unstable nucleus that break spontaneously with emission of radiation and release of large amount of energy in achieving a stable composition .isotopes are element with equal nucleus of proton but different numbers of neutron in nucleus .
Examples of Radioactive element are carbon 14; uranium -238, cobalt-60,uranium-235, hydrogen-3 radium -241 thorium-232, potassium-40.
TYPES OF RADIATION AND PROPERTIES
- ALPHA EMISSION –[α]radioactive or radio isotopes emits an alpha particles which is represented [He].The mass number of the radioactivity isotope is reduced by 4 and the atomic number also reduced by
PROPERTIES OF ALPHA EMISSION
- it is positively charge .
- it has penetrating power and can be stopped by sheet of paper .
- it can be deflected by towards the negatively plate in an electrostatic field since they are positively
- it has high ionizing power .
- it has helium particles.
- BETA EMISSION –[β] when a radioactive isotope element emission beta particle, the atomic number is increased by 1. This does not affect the mass number. Beta particle is represented by i.e. A proton with the loss of an electron with escape of Beta particles.
PROPERTIES OF BETA EMISSION .
- The particle is negatively charged.
- It has a relatively small mass.
- They are deflected to the positive plate in an electrostatic field.
- It has more penetrating power than alpha particle.
- It has lower ionizing power than alpha particle.
- GAMMA(γ) EMISSION – gamma ray is represented by [γ] it is often emitted along alpha and beta particles
PROPERTIES OF GAMMA EMISSION
- gamma rays are electron magnetics waves similar to visible light
- 2.it has least ionizing power
- it has most penetrating power than alpha & beta
- it causes fluorescence in sodium iodine and zinc sulphate.
- it is un affected by electrostatic field .
TYPES OF NUCLEUR REACTION
- 1. NUCLEAR FISSION –this is the breaking down or splitting of heavy radioactive isotopes to produce smaller [lighter] isotopes of other element.
- 2. NUCLEAR FUSION – this is when two or more light nucleus come together to form a heavy nucleus
X-rays are electromagnetic waves. They penetrate through most solid materials . soft x-rays are used in medicine to take photographs of human body parts it is also used in study the arrangement of particles in crystal .lattice especially protein.
USES OF RADIOACTIVITY.
- It is used in generating electricity
- It is used in curing cancer or cancer treatment
- In food industry it is used to kill decay causing bacteria and mould
- It is used as a tracer
- It is used in carbon dating to determine the age of specimen