DEFINITION OF RADIOACTIVITY

 

Written By; WILSON UCHECHUKWU LUCKY AMAKODI.

Email contact; wilsonlucky37@gmail.com

Website; WILSON LUCKY BLOG

Phone no; 08145010904

WHAT IS RADIOACTIVITY

Radioactivity is the spontaneous decay or disintegration of some certain heavy elements(e.g,uranium,radium) with unstable type of atomic nuclei.During disintegration the radioactive atom emits high energy particles or radiations which could be alpha,beta or gamma rays.This spontaneous emission of radiations will continue until the radioactive nuclei become stable.

The radiations have penetrating power,affect photographic plates,causes gases to ionize and make certain substances to fluoresce e.g Zn S.

Radioactivity was first discovered and investigated in 1896 by Henri Becquerel who discovered that Uranium salts emitted rays.He observed that a photographic film  which was well protected from light became blackened when it was accidentally placed near a uranium salt.

TYPES OF RADIATION OR EMISSION:

There are three different types  of radiations:

The alpha,beta and gamma rays.They have different penetrating powers.

Rutherford discovered the nature those radiations being emitted by radioactive elements by placing a very small piece of radium in a small hole dug in a lead block and applying a magnetic field to the radiation via alpha,beta and the gamma rays.

He observed that both the alpha and the beta particles were deflected under the magnetic field and electric field in opposite directions while gamma rays were not deflected at all.

picture of the deflection of alpha,beta and gamma rays.

1. ALPHA RADIATION:When the nucleus of an atom loses an alpha particle i.e, a helium nucleus during disintegration, the atomic number of the atom is reduced by two units and it's mass number by four units.

PROPERTIES OF ALPHA RAYS:

1.Alpha rays are positively charged

2.they are therefore deflected to the negative plate in an electric field.

3.they have low penetrating power(low energy) and because of their longer wave-lengths,they cannot pass through a piece of paper.

4.they are very powerful ionizing effects upon any gas through which the pass.

5.they also cause some substance like Zinc sulfide to Florence.

2. BETA RADIATION:This kind of radioactive change is equivalent to the splitting of a neutron in the atomic nucleus of the radioactive element into an electron and a proton which remains in the nucleus.The mass number does not change but the atomic number  increases by one.

PROPERTIES OF BETA-RAYS(PARTICLE)

1.These rays are very fast moving streams of electrons.

2.they are negatively charged.

3.they are therefore deflected to the positive plate in an electric field.

4.they have high penetrating power than alpha particles with their shorter wave length,they would only pass through a piece of paper but not through a piece of aluminium which is metallic.

5.they have low ionizing effect on gases.

6.beta rays also caused fluorescence in substance like anthracene but not Zinc sulfide.

3.GAMMA RADIATION:In gamma decay, only energy is released and on change in the mass number or atomic number. It accompanies alpha or beta decay.

PROPERTIES OF GAMMA RAYS:

1.Gamma rays are electromagnetic waves similar to light but are of shorter wave length than light rays and have higher frequency.

2.they are negligible 

3.they do not have mass or charge.

4.they travel at the speed of light.

5.gamma rays have high penetrating power,out of the three types of radioactive emission they are the most penetrating (i.e,they have high amount of energy)

6.Gamma rays have the least ionizing power.

WHAT IS RADIOACTIVE DECAY?

During  radioactive decay,the mass number of the disintegrated element must be equal to the sum of the mass numbers of the radiation lost and that of the resulting element.A decay is said to have occur when a certain quantity of a radioactive material disintegrates spontaneously.

The rate of decay depends on the radioactive material and varies from materials to material.

The type of radiation produced will decide the nature of the atom formed.

In Alpha decay, the atomic number of the atom is reduced by two units and it's mass number by four units.

During Beta decay,the neutron is splitted into an electron and a proton which remains in the nucleus.The mass number does not change but atomic number increases by one.

While during gamma decay, only energy is released  and no change in the mass number  or atomic number.

WHAT IS HALF-LIFE?

Half - life of a radioactive elements is the time taken for half  of the atoms initially present in the element to decay. 

WHAT IS RADIOACTIVE ISOTOPE?

Radioactive isotopes are isotopes that are made artificially  by bombarding neutrons or protons at elements.

ATOMIC ENERGY BY FISSION AND FUSION:

Atomic energy can be released by the fission(breaking up) of the nuclei of heavy elements and also by the fusing (combination of two or more) of the nuclei of light elements.

In both cases,the product is less than the reactants because there is a considerable release of atomic energy.(i.e,the  mass lost is converted to energy).

The energy released in nuclear fission are used in power stations and nuclear submarines.

While the energy released in nuclear fusion is applied in the making of hydrogen bombs.

picture of fission and fusion.

Written By; WILSON UCHECHUKWU LUCKY AMAKODI.

Email contact; wilsonlucky37@gmail.com

Website; WILSON LUCKY BLOG

Phone no; 08145010904