A breif describtion about Isotope and nature of radioactivity, Radioactive decay i.e. Alpha decay, Beta decay, Gamma decay

1. Supervised by-
Mr. Gagan kumar panighrahi
Presented by- IPSITA SAHOO
Reg. no- 200705180160

2. CONTENTS
Isotopes and their examples
Radioactivity, how it occurs and its nature
Radio active decay
Properties of alpha beta gamma
Radio active decay; Alpha decay
Radio active decay; Beta decay
Radio active decay; Gamma decay
References

3.  The term isotope is formed from the Greek roots isos (ἴσος "equal") and topos (τόπος"place"), meaning "the
same place"; thus, the meaning behind the name is that different isotopes of a single element occupy the same
position on the periodic table.
 It was coined by Scottish doctor and writer Margaret Todd in 1913.
Isotopes are two or more types of atoms that have the same atomic number (number of protons in
their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ
in nucleon numbers (mass numbers) due to different numbers of neutrons in their nuclei.
 All isotopes of a given element have almost the same chemical properties, they have different atomic masses
and physical properties.
ISOTOPE

4.  Radioactivity is the spontaneous degradation of nucleus & transmission of one element to another with
consequent emission of rays ( or ) particles.
 Radioactivity First discovered in 1896 by the French scientist Henri Becquerel, after whom the SI unit for
radiation, the Becquerel, is named.
 Radioisotopes/radioactive isotopes of an element can be defined as atoms that contain an unstable nucleus and
dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta and gamma rays.
Radioactivity
 Naturally- as in radium-226,
Carbon-12
 Artificially altering the atoms
by using a nuclear reactor or a
cyclotron.
Most of the isotopes which occur naturally are stable. A
few naturally occurring isotopes and all of the man- made
isotopes are unstable.
 Unstable isotopes can become stable by releasing different
types of particles. This process is called radioactive decay
and the elements which undergo this process are called
radioactive isotopes/radioisotopes/radionuclides.
Nature of Radioactivity

5.  Radioactive decay (also known as nuclear
decay, radioactivity, radioactive disintegration or nuclear
disintegration) is the process by which an unstable atomic nucleus
loses energy by radiation.
 A material containing unstable nuclei is considered radioactive.
 Three of the most common types of decay are alpha decay (𝛼-
decay), beta decay (𝛽-decay), and gamma decay (𝛾-decay), all of
which involve emitting one or more particles.
Radioactive decay
Properties of Alpha, Beta, Gamma Penetrating power

6.  When a nucleus undergoes alpha decay, the parent nucleus will suffer a decrease in atomic number (Z) of
two and a decrease of four in mass number (A).
 The daughter nucleus is now a different element.
 Alpha Decay Example
An example of the form of decay occurs in uranium 238.
The equation represents what occurs is
Alpha particles are not penetrating.
Their only biological effects are to the surface of the skin, with the production of radiation ‘burns’.
Radioactive Decay; Alpha Decay
Biological Effects Of Alpha

7.  When a nucleus undergoes beta decay, the parent nucleus will suffer a decrease in atomic number (Z) by one
while the atomic mass (A) is unchanged.
 Betas are physically the same as electrons, but may be positively or negatively charged.
 Beta decays are of 2 types
A. Beta minus decay
B. Beta plus decay
ß- emission is a process in which, essentially a neutron in
the nucleus is transformed into a proton and electron .
 The electron(e-) and the neutrino(v) are ejected from
the nucleus and carry away the energy released in the
process as kinetic energy. The electron is called a ß-
particle and the neutrino is a “particle“ having no mass or
electrical charge.
Beta (ß-) minus decay
 Occurs in proton-rich nuclides
 A proton in the nucleus is transformed into a
neutron and a positively charged electron
 The positively charged electron or positron (ß+)
and a neutrino are ejected from the nucleus
Beta (ß+) plus decay
Radioactive Decay; Beta Decay
Ex-
Ex-

8.  In gamma decay, a nucleus changes from a higher energy state to a lower energy state through the emission
of electromagnetic radiation (photons).
 The number of protons (and neutrons) in the nucleus does not change in this process, so
the parent and daughter atoms are the same chemical element.
 Gamma radiation has a very high frequency with short wavelength.
 Gamma emission are in two forms
A. Isomeric transition
B. Internal conversion
 A nucleus in an excited state may reach its ground
or unexcited state by the emission of gamma ray.
 An example of this type of decay is that of
technetium 99 m
A. Isomeric transition
 In Internal Conversion the excess energy of an
excited nucleus given to an atomic electron.
 Example of this type of radioactive decay occurs
in iron 55 which decays into manganese-55.
The reaction can be represented as
Mass number unchanged in this form of decay &
that the atomic number is decreased by 1
B. Internal conversion
Radioactive Decay; Gamma Decay

9. References
 "Radioactivity", Encyclopædia Britannica. 2006. Encyclopædia Britannica Online
December 18, 2006
 "Radioactivity: Weak Forces" Radioactivity. EDP Sciences. Retrieved 4
March 2020.
 "3. Nuclear and Atomic Spectroscopy". Spectroscopy. Methods in Experimental
Physics.