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It means that after bombardement with neutron of , isotope is occured and one particle is emitted.
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There are important differences between chemical reactions and nuclear reactions
• Number of valence electrons in chemical reactions are changed while the nucleus changes in nuclear reactions.
• The chemical properties of the isotopes of an element are the same. but the elemental isotopes give different nuclear reactions.
• The mass is preserved in the chemical reactions. In nuclear reactions the mass is not protected.
• Energy exchange in nuclear reactions much more than the energy change in the chemical reactions.
There are 2 varieties of radioactivity:
• Induced radioactivity (artificial radioactivity): When a stable nucleus is bombarded with some particles, the nucleus becomes radioactive.
• Natural radioactivity: Unstable isotopes in nature cause this radioactivity. The half-lives of these isotopes are very long and they are another radioactive decomposition product. The discovery of natural radioactivity has led to significant developments in nuclear structure and nuclear mechanisms.
In addition, radioactivity has provided important information on basic interactions, ie reaction mechanisms.
Radioactive decomposition reactions are first grade reactions and calculations related to this are done as described in the chemical kinetic section.
Nucleus outside of the stationary zone are unstable and radiate.
These can be grouped into three groups:
• The unstable nucleus resides somewhere above the stability circle: The neutron / proton ratio in these nucleus is high.
There are 2 ways in which they can enter the stable zone:
a) Neutron is removed,
b) Increase the number of protons (electrons are discarded).
• The unstable core is located under the stability circle:
The neutron / proton ratio in these nucleus is small. There are 3 ways in which they can enter the stable zone:
a) Neutron must increase
b) The number of protons should decrease c) Positron should be emitted.
• No matter what the neutron number of the unstable core is, the number of protons is very high. This nucleus in this case can not be stabilized in the ways mentioned above. These are nucleus that go well beyond the stability circle (atomic number 84 elements large elements). These nucleus can only emitted large particles to small atomic numbers and masses.
RADIOCHEMISTRY
Radiochemistry is a chemical branch that the radioactive materials are used. These materials can easily be viewed with photographic paper or a Geiger-Müller device.
It is a container full of argon. Electrodes are placed on the top and bottom. Radiation from the radioactive materials enters the thin- walled window and breaks the electrons from the argon atoms, causing Ar + ions to form. A potential between 1000-1200 V is applied between the electrodes of the tube. The electrons and Ar + ions that form in the tube move in pulses from electrode to electrode and allow electric current to pass through. These pulses are amplified in an amplifier (amplifier) and converted to sound and counted by sending an automatic counter
Radiochemistry is used for age determination of various samples. In addition, radiochemicals are used especially in cancer treatment and imaging.
Factors affecting radioactivity
1) The most important factor affecting the radioactivity of a substance, the nucleus of the atoms of matter. The imbalance of the number of neutron proton in the nucleus causes radioactivity.
2) Temperature also affects radioactivity. As temperature increases, radioactive the speed of disruption is reduced.
Fission: The mass number is too large (heavy) the atomic nucleus is divided into smaller nuclei. The reaction results in unstable nuclei and neutrons. It is usually divided into two small nuclei, and the neutrons emerge during division. It also comes with high energy.
Fusion: Two or more of the less stable your small nucleus combines to form larger (heavier) nuclei. The energy released is much bigger than the charge But to start the fusion event, an activation energy is absolutely necessary, and this necessary activation energy is very high.The best example of fusion is the hydrogen bomb and the activation energy is provided by an atom bomb.