Radioactivity Alpha Decay

Bookmark added to your notes.
View Notes

What is Radioactivity?

Unstable atomic nuclei do not have intense binding energy due to the overload of neutrons and protons, thus exhibiting radioactivity. These particles emit electromagnetic energy due to nuclear instability. Radiation is emitted in several radioactive decays including alpha, beta, and gamma. Radioactivity causes loss of energy, causing further instability, an increase in the size of the nucleus, and concentrated mass.  

Radioactivity Definition Chemistry

Radioactivity in chemistry can be defined as a phenomenon that deals with the spontaneous emission of radioactive particles causing the nuclear reaction. In the phenomenon of radioactivity, the unstable atomic nucleus loses significant energy and is processed under three heads, namely, alpha-beta and gamma. 

(Image to be added soon)

The image illustrates the penetration of alpha, beta and gamma particles through paper, lead and aluminium. Alpha particles are stopped by the paper sheet, beta particles are stopped by the aluminium sheet whereas gamma particles successfully penetrated through lead. 

Alpha Decay And Its Occurrence 

Alpha decay is a significant type of radioactive decay in which the unstable nuclei of the atom can emit alpha particles to get converted into a stable element. The alpha particle has two protons, i.e. subatomic positive ions and neutrons, i.e. two subatomic neutrally charged ions. These subatomic particles have their configuration ratio altered in the process of radioactivity causing characteristic changes. The mass number is altered and reduced by four, whereas the atomic number is reduced by two. The radiation caused by the alpha particles is hazardous for human health, and in case inhaled or ingested it can lead to lung cancer. There are only a handful of elements that can undergo alpha decay since it requires the nucleus of the element to be unstable and large to withstand the fission changes. The alpha particles have a five percent speed of light, and the energy level varies around 5MeV. The alpha particles have a positive charge since there are no electrons in the shell; thus, the particles have a mass. The absence of electrons leads the alpha particle to vigorously react with the matter in the environment through which it loses its energy. The heavy particles because the radioactive decay process reacts with the human body, heavy enough to harm the body tissues. At times, the overdose leads to blisters and burns. 

Uses Of Radioactivity

Radioactive particles have scores of applications in several fields outside nuclear weaponry.


Radioactive isotopes have extensive use in diagnosis and therapy which work as effective tracers. In hospital settings, X-Ray, PET, and CT scan machines are used to diagnose and monitor medical conditions. Radionuclides are used to treat cancers, thyroid, and hyperthyroidism. Significant radioactive tracers are used to trace cardiac stress with the help of Technetium-99. The isotope can be used to identify arteries and areas near the heart, which are resulting in blood flow to diminish. Radiography involves using radioactive particles to detect structural anomalies and irregularities in the basic bone structure.


Strong radiations are used to root out the presence of toxic and dangerous pollutants released by the power plants in the lush environment. The agricultural industry uses this phenomenon for controlling the breeding of insects and exposing the radiation to make hybrid plants. Engineers use radioactive particles to measure moisture in soil profiles, fluid levels in liquids, construction material and detect defects in the welding and casting process of metal. 

 Effects Of Radioactive Energy On Human Health 

Radioactive radiation can cause both long term and short term effects on the human body. It is completely dependent on the dose of radiation which comes in contact with the body

Radiation poisoning can cause nausea and organ damage to lymph nodes and bone marrow. 

Strong radiation levels can cause haemorrhage and skin peeling, which at times can even lead to death. When the human body is vulnerable to high doses in a short period, the damage done is acute. The radioactive radiation kills significant cells in the human body, and it takes a long span to recover the damage done. At times, the body can be penetrated with radiation in case of the infected food chain, inhalation and indigestion, causing long term health effects. The alpha decay particles are absorbed by the human body, causing danger to health. The isotopes undergo beta-decay of the iodine element can cause thyroid cancer, and the absorbed dose is enough for causing death. 

Did You Know?

Radon is the first radioactive isotope that proposed lung cancer in humans, and the radium decays affected the German miners in 1913. 

FAQ (Frequently Asked Questions)

1. How Far Can The Radioactivity Radiation Travel And How?

The travel distance of the radioactive particles depends on the type of radiation, and so does the penetration power of the particles. The alpha radiation particles and beta radiation particles cannot travel far and can be blocked without any hassle. On the contrary, the gamma rays are very difficult to block concerning the significant distance they travel. The neutrons and x-rays can travel far as well and are generally used for industrial and academic applications. The penetrating radiation can only be blocked with thick hydrogen packed materials.

2. For What Purposes Are The Radioactive Particles Used?

Generally, the radioactive particles are used for medical purposes, especially for therapeutic and diagnostic purposes. In certain biomedical research, the radioactive materials are used for testing the novel drugs and studying the bone formation and evolving cellular functions in the mammals. Furthermore, radioactive elements can be used for industrial applications including, locating new sources for energy, protection of blood and staple food supplies, warning fires, increasing town road and highway safety and lighting the emergency exit doors.