TỔNG ÔN TẬP THI VÀO LỚP 10 MÔN TIẾNG ANH NĂM HỌC 2023 - 2024 CÓ ĐÁP ÁN (NGỮ Â...
Radiobiology1
1. Prof.Dr.Tarek Elnimr L 1 Presented to the Biology Departments in Faculty of Sciences on February 15 , 2009
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4. A X N Z SYMBOL OF ELEMENT MASS NUMBER (the number of protons and neutrons) ATOMIC NUMBER (the number of protons) 53 I 78 131 Example: 131 I or I-131 The number of neutrons
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7. Isotopes I Atoms having the same atomic number are called isotopes A=131 A= 127 Z= 53 Same Z= 53 N= 78 N= 74
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11. Isotones Atoms having the same number of neutrons are called isotones X Y A=131 A= 127 N= 53 Same N= 53 Z= 78 Z= 74
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14. Isobars Atoms having the same mass number are called isobars I Xe A=131 A= 131 Z= 53 Same Z= 54 N= 78 N= 77
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17. Isomers Similar atoms having different internal energy are called isomers Tc Tc A=99m A= 99 Z= 43 Same Z= 43 N= 56 N= 56 i
Part 2. Radiation Physics Radiation Protection in Nuclear Medicine
Part 2. Radiation Physics Radiation Protection in Nuclear Medicine The lecture assumes familiarity with basic physics concepts - the present slide allows the lecturer to review the basic atomic model and the nomenclature for isotope labeling.
An atomic nucleus is characterized by the number of neutrons and protons it contains. The number of protons determines the atomic number of the atom, Z. As mentioned earlier, this determines also the number orbital electrons in the electrically neutral atom and therefore the chemical element to which the atom belongs. The total number of nucleons (protons + neutrons) is the mass number of the nucleus, A. The difference, A-Z, is the neutron number, N. The notation now used to summarize atomic and nuclear composition is A Z X N, where X represents the chemical element to which the atom belongs. For example, an atom comprising 53 protons, 78 neutrons (and thus 131 nucleons) and 53 orbital electrons represent the element iodine and is symbolized by 131 53 I 78 . Since all iodine atoms have atomic number 53, either the “I” or the “53” is redundant, and the “53” can be omitted. The neutron number, 78, can be inferred from the difference 131-53 and also can be omitted. Therefore a shortened but still complete notation for this atom is 131 I. An acceptable alternative in terms of medical terminology is I-131.
Part 2. Radiation Physics Radiation Protection in Nuclear Medicine Rutherfors is displayed here as the father of the model of the atom with a central nucleus. It can be mentioned that he supervised 11 students which all were rewarded the nobel prize. He got it himself too (in chemistry).
ISOTOPES Atoms with the same number of protons and different number of neutrons are called ISOTOPES. An isotope may be defined as one or two or more forms of the same element having the same atomic number (Z), differing mass numbers (A), and the same chemical properties. These different forms of an element may be stable or unstable (radioactive). However, since they are forms of the same element, they possess identical chemical properties. The simplest atom is the hydrogen atom. It has one electron orbiting a nucleus on one proton. Any atom which has one proton in the nucleus is a hydrogen atom, like both of the ones shown here. Hydrogen - 3 is called tritium. While their chemical properties are identical their nuclear properties are quite different. Hydrogen - 3 is radioactive and hydrogen - 1 is stable. Why are some nuclides radioactive? The stable isotopes of elements have very definite ratios of neutrons to protons in their nuclei. As the atomic mass number increases, the ratio of neutrons to protons increases according to a definite pattern. If isotopes vary from this pattern, they are relatively unstable. The most stable state of a nucleus is called the ‘ground ‘ state. In an unstable nucleus the nucleons are in an ‘exited’ state and must release energy to reach the ground state. In the transformation of an unstable nucleus to a more stable nucleus, energy is emitted in the form of particles such as alpha and beta particles, and in some cases photons (gamma rays). This is the process of radioactive decay . When the atom rearranges itself we call the event decay or disintegration. The number of atoms decaying during a given time is dependent on the total number present and the stability of the atom. The time it takes for half of the material to decay is called the "HALF-LIFE" of the material.
Part 2. Radiation Physics Radiation Protection in Nuclear Medicine Rutherfors is displayed here as the father of the model of the atom with a central nucleus. It can be mentioned that he supervised 11 students which all were rewarded the nobel prize. He got it himself too (in chemistry).
Part 2. Radiation Physics Radiation Protection in Nuclear Medicine Rutherfors is displayed here as the father of the model of the atom with a central nucleus. It can be mentioned that he supervised 11 students which all were rewarded the nobel prize. He got it himself too (in chemistry).
Part 2. Radiation Physics Radiation Protection in Nuclear Medicine Rutherfors is displayed here as the father of the model of the atom with a central nucleus. It can be mentioned that he supervised 11 students which all were rewarded the nobel prize. He got it himself too (in chemistry).
Part 2. Radiation Physics Radiation Protection in Nuclear Medicine Rutherfors is displayed here as the father of the model of the atom with a central nucleus. It can be mentioned that he supervised 11 students which all were rewarded the nobel prize. He got it himself too (in chemistry).
![THE ATOM ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Particle Symbol Mass Energy Charge (kg) (MeV) ---------------------------------------------------------- Proton p 1.672*10 -27 938.2 + Neutron n 1.675*10 -27 939.2 0 Electron e 0.911*10 -30 0.511 -](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)