Isotopes, Radioactive Isotopes, Examples of Isotopes. We have learnt how electrons involve in stabilisation of an atom. What’s about Proton? Has there been no role for them? Has there been any way to express the number of protons in an atom? The answer is “YES”. Protons and neutrons are also known as the nucleons. The number of protons in the nucleus is known as the atomic/proton number of the particular element. It is conventionally represented by the symbol Z. Since an atom having no charge, means the number of electrons must be equal to the number of protons that is the atomic number. Hence, in an atom the atomic number is also equal to the number of electrons. All atoms have a certain value of mass number which is derived as follows. Hence, the sum of number of proton and neutron is known as mass number. Uranium-thorium dating, also called thorium-230 dating, uranium-series disequilibrium dating or uranium-series dating, is a radiometric dating technique commonly used. The number of neutrons, N, is known as the number of neutrons in an atom. Thus, A = Z + NThe mass of protons and neutrons have approximately same, hence the atomic mass of an atom is equal to A. Uranium (92 U) is a naturally occurring radioactive element that has no stable isotopes but two primordial isotopes (uranium-238 and uranium-235) that have long half. What are isotopes? Learn more about characteristics, atomic mass and uses of isotopes, radioactive and stable isotopes. Also find table, examples and problems of.
On the basis of atomic number and mass number, elements can be classified as isotopes, isobars and isotones. Let’s discuss about isotopes with some common examples. Properties such as melting point, boiling point, density etc., which depend upon the atomic mass should be different for different isotopes because the isotopes of an element have different masses. The sum of the masses of these constituent particles in a given isotope of an element is known as its atomic mass. Atomic mass of an isotope = Mass of neutrons + Mass of electrons + Mass of protons. Since mass of an electron is practically nil, in the range of 0. Atomic mass of an isotope = Mass of neutrons + Mass of protons. Also, we know that the mass number of an isotope is a whole number. Now, since the atomic masses of an isotope of an element are generally a fractional number, the mass number of that isotope which should be a whole number is obtained by rounding off the value of the atomic masses of that isotope to the nearest whole number. For example, since two isotopes of chlorine have atomic masses equal to 3. Hydrogen atom (Z=1) has no neutrons. Atoms of elements having the same atomic number with different mass numbers are called isotopes. Protium Deuterium Tritium. At. mass = 1 At. mass = 2 At. Now, since they have different mass numbers, they have a different number of neutrons in their nuclei. Thus, the number of protons (p), neutrons (n) and electrons (e) in an isotope with atomic number, Z and mass number A is given by these following relations. Number of protons = p = ZNumber of neutrons = n = A - ZNumber of electrons = e = ZMany elements exhibit more than one form and so have a lot of isotopes. The table below shows the list of isotopes exhibited by elements. Oxygen. Isotopes Atomic number Mass number Electrons. Protons Neutrons 1. O8 1. 6 8 8 1. 6 - 8 = 8 1. O 8 1. 78 8 1. 7 - 8 = 9 1. O8 1. 8 8 8 1. 8 - 8 = 1. Hydrogen. There are three isotopes of hydrogen with mass numbers 1, 2 and 3 and atomic number 1. Isotopes. Atomic number. Mass number. Electrons. Protons. Neutrons. H – Protium. 1 1 1 1 1 - 1 = 0 2. H- Deuterium 1 2 1 1 2 - 1 = 1 3. H- Tritium 1 3 1 1 3 - 1 = 2 Neon. Neon has three isotopes with atomic number 1. Isotopes. Atomic number. Mass number. Electrons. Protons. Neutrons. Ne 1. 0 2. 0 1. 0 1. Ne 1. 0 2. 1 1. 0 1. Ne 1. 0 2. 2 1. 0 1. Chlorine. Chlorine is a mixture of two isotopes with atomic number 1. Isotopes. Atomic number. Mass number. Electrons. Protons. Neutrons. Cl 1. 7 3. 5 1. 7 1. Cl 1. 7 3. 7 1. 7 1. Isotopes of elements like hydrogen, chlorine, neon, oxygen, etc., exist in nature and are stable. But isotopes of some elements are radioactive in nature and are not quite stable. Example: Isotopes which are radioactive in nature are called radioisotopes. Uranium has two isotopes, U - 2. Uranium. When Uranium was bombarded with slow electrons, U - 2. U - 2. 39 is a radioisotope with a half life period of 2. Neptunium, with mass number 2. Thus, this isotope of Uranium has a very small life cycle and so, is unstable. As much as 2. 0 isotopes of neptunium were formed during their radioactive reactions with mass numbers ranging from 2. Similarly, Plutonium, Pu has two isotopes, both radioactive. They had mass numbers Pu - 2. Pu - 2. 39. They both disintegrate to give two important trans uranium elements, Americium, Am, with mass number 2. Curium, with atomic number 9. Radioisotopes are used as radioactive tracers. Radioactive isotopes have a property by which they can be easily detected and estimated quantitatively. They are also used in studying the reaction mechanisms of complicated reactions like photosynthesis, hydrolysis of esters, etc. Radioactive isotopes are used as a tracer to diagnose many diseases. This is a very important use of radioisotope. The presence and location of a brain tumor, to detect the circulation of blood, to check the pumping action of blood, function of thyroid gland, etc. The relative mass of $^. Calculate the atomic mass of a naturally occurring sample of lithium. Solution: Atomic mass = $\frac?
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