DOCSLIB.ORG

Average Atomic Mass of Isotopes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Average Atomic Mass of Isotopes Learn Chemistry with me in English Language The Problems which you Face! The Problems which you Face! Doubts? Notes? Tests & Assignments? Competitive Exams? Choice of Schedule? Choice of Language? Problems SOLVED! Doubts! Notes! Tests & Assignments! Competitive Exams! Schedule! Choice of Language! BONUSES! Unlimited Live Classes! All Micro & Crash Courses! Performance Reports! Personalised Attention! Just VISIT! Link in the Desc & Pinned comment CHOOSE YOUR GRADE CHOOSE YOUR BOARD CHECK OUT THE DETAILS CLICK ON GET SUBSCRIPTION CLICK ON GET SUBSCRIPTION 1 Month Before Coupon After Coupon AGPRO 3 Months Before Coupon After Coupon AGPRO 6 Months Before Coupon After Coupon AGPRO Just VISIT! Link in the Desc & Pinned comment Coupon CODE! AGPRO Learn Chemistry with me in English Language Learning Objectives Atomic number & mass Number Let’s start ATOMIC NUMBER It is the number of protons of an atom, which determines its atomic number It is denoted by ‘Z’ ATOMIC NUMBER All atoms of an element have the same atomic number ATOMIC NUMBER Elements are defined by the number of protons they possess For hydrogen, Z = 1, because in hydrogen atom, only one proton is present in the nucleus. ATOMIC NUMBER the atomic number is defined as the total number of protons present in the nucleus of an atom Mass number ➢ mass of an atom is practically due to protons and neutrons alone. ➢ These are present in the nucleus of an atom. ➢ Hence protons and neutrons are also called nucleons. Mass number ➢ Carbon is 12 u because it has 6 protons and 6 neutrons, 6 u + 6 u = 12 u. Mass number the mass of aluminium is 27 u (13 protons+14 neutrons). Mass number The mass number is defined as the sum of the total number of protons and neutrons present in the nucleus of an atom Notation for representation of Element In the notation for an atom, Notation for representation of Element , NotationMass for representation number of Element Isotopes ➢ atoms of some elements have which have the same atomic number but different mass numbers. Isotopes For example, take the case of hydrogen atom, Isotopes Some more examples :, Isotopes of Carbon Isotopes of Oxygen Isotopes of Chlorine How to define Isotopes ? How to define Isotopes ? ➢ isotopes are defined as the atoms of the same element, having the same atomic number but different mass numbers. ➢ Important points about Isotopes ➢ elements consist of a mixture of isotopes. ➢ Each isotope of an element is a pure substance. ➢ The chemical properties of isotopes are similar but their physical properties are different ➢ Isotopes ➢ Chlorine occurs in nature in two isotopic forms, with masses 35 u and 37 u in the ratio of 3:1. ➢ Isotopes ➢ what should we take as the mass of chlorine atom? ➢ Average atomic mass of isotopes ➢ The mass of an atom of any natural element is taken as the average mass of all the naturally occurring atoms of that element ➢ Atomic mass of a single isotope ➢ If an element has no isotopes, then the mass of its atom would be the same as the sum of protons and neutrons in it. ➢ Average atomic mass of isotopes ➢ But if an element occurs in isotopic forms, ➢ the percentage of each isotopic form and then the average mass is calculated. ➢ Average atomic mass of isotopes ➢ The average atomic mass of chlorine atom, on the basis of above data, will be ➢ Average atomic mass of isotopes ➢ Isotopes ➢ This does not mean that any one atom of chlorine has a fractional mass of 35.5 u. ➢ It means that if you take a certain amount of chlorine, it will contain both isotopes of chlorine and the average mass is 35.5 ➢ Applications of Isotopes some isotopes have special properties which find them useful in various fields ➢ Applications of Isotopes An isotope of uranium is used as a fuel in nuclear reactors ➢ Applications of Isotopes An isotope of cobalt is used in the treatment of cancer ➢ Applications of Isotopes An isotope of iodine is used in the treatment of goitre ➢ ISOBARS ➢ Let us consider two elements — calcium, atomic number 20, and argon, atomic number 18. ➢ The number of electrons in these atoms is different, but the mass number of both these elements is 40 ➢ ISOBARS ➢ Atoms of different elements with different atomic numbers, which have the same mass number, are known as isobars. 1. Write 2 differences between Isotopes & Isobars. 2. What is the relation between the no of protons(p) , no of neutrons(n) & mass number(A). Today’s Session ❖ Atomic number & mass number Next session ❖ Doubts & Menti CHOOSE YOUR GRADE CHOOSE YOUR BOARD CHECK OUT THE DETAILS CLICK ON GET SUBSCRIPTION CLICK ON GET SUBSCRIPTION 1 Month Before Coupon After Coupon AGPRO 3 Months Before Coupon After Coupon AGPRO 6 Months Before Coupon After Coupon AGPRO Just VISIT! Link in the Desc & Pinned comment Coupon CODE! AGPRO chemistry.vedantu_ anubhagaur Reach out to me @ [email protected] .
Load more

Recommended publications
  • Chlorine Stable Isotopes in Sedimentary Systems: Does Size Matter?
    Chlorine stable isotopes in sedimentary systems: does size matter? Max Coleman Jet Propulsion Laboratory, Caltech, Pasadena, California, USA ABSTRACT: Stable isotope abundances vary because of size (atomic mass) differences. The chlorine stable isotope system was one of the first described theoretically, but had a slow, disappointment-strewn develop- ment, relative to other elements. Method improvement gave only small, but significant, differences (-1 %.) in compositions of geological materials. Eventually, brines and groundwater chlorides gave larger differences (-5%0). Physical processes like diffusion and adsorption, probably are the main controls of groundwater com- positions. In contrast, the processes producing brine compositions are still enigmatic and need further work for full understanding. Recent work on anthropogenic groundwater contaminants (chlorinated aliphatic hy- drocarbons and perchlorate) shows variations resulting from manufacturing processes; implying possibilities of tracing sources. However, they are subject to microbial degradation, producing much larger fractionations (115%0),but therefore offering better possibility of monitoring natural attenuation. So atomic size is important to give isotopic fractionation and the size of fractionation matters, allowing observation of otherwise unde- tectable processes. lecular and atomic weights by weighing the gases and relating them to the weight of hydrogen. All 1 INTRODUCTION atomic weights were integer multiples the weight of This paper aims to give a short and selective
    [Show full text]
  • 12 Natural Isotopes of Elements Other Than H, C, O
    12 NATURAL ISOTOPES OF ELEMENTS OTHER THAN H, C, O In this chapter we are dealing with the less common applications of natural isotopes. Our discussions will be restricted to their origin and isotopic abundances and the main characteristics. Only brief indications are given about possible applications. More details are presented in the other volumes of this series. A few isotopes are mentioned only briefly, as they are of little relevance to water studies. Based on their half-life, the isotopes concerned can be subdivided: 1) stable isotopes of some elements (He, Li, B, N, S, Cl), of which the abundance variations point to certain geochemical and hydrogeological processes, and which can be applied as tracers in the hydrological systems, 2) radioactive isotopes with half-lives exceeding the age of the universe (232Th, 235U, 238U), 3) radioactive isotopes with shorter half-lives, mainly daughter nuclides of the previous catagory of isotopes, 4) radioactive isotopes with shorter half-lives that are of cosmogenic origin, i.e. that are being produced in the atmosphere by interactions of cosmic radiation particles with atmospheric molecules (7Be, 10Be, 26Al, 32Si, 36Cl, 36Ar, 39Ar, 81Kr, 85Kr, 129I) (Lal and Peters, 1967). The isotopes can also be distinguished by their chemical characteristics: 1) the isotopes of noble gases (He, Ar, Kr) play an important role, because of their solubility in water and because of their chemically inert and thus conservative character. Table 12.1 gives the solubility values in water (data from Benson and Krause, 1976); the table also contains the atmospheric concentrations (Andrews, 1992: error in his Eq.4, where Ti/(T1) should read (Ti/T)1); 2) another category consists of the isotopes of elements that are only slightly soluble and have very low concentrations in water under moderate conditions (Be, Al).
    [Show full text]
  • Accelerator Mass Spectrometry of 36Cl and 129I Analytical Aspects and Applications
    Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1 Accelerator Mass Spectrometry of 36Cl and 129I Analytical Aspects and Applications BY VASILY ALFIMOV ACTA UNIVERSITATIS UPSALIENSIS ISSN 1651-6214 UPPSALA ISBN 91-554-6124-7 2005 urn:nbn:se:uu:diva-4725 Dissertation presented at Uppsala University to be publicly examined in Häggsalen, The Ång- ström Laboratory, Uppsala, Friday, January 21, 2005 at 10:15 for the Degree of Doctor of Philosophy. The examination will be conducted in English. Abstract Alfimov, V. 2005. Accelerator Mass Spectrometry of 36Cl and 129I: Analytical Aspects and Applications. Acta Universitatis Upsaliensis. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1. 81 pp. Uppsala. ISBN 91-554-6124-7 36 129 Two long-lived halogen radionuclides ( Cl, T1/2 = 301 kyr, and I, T1/2 = 15.7 Myr) have been studied by means of Accelerator Mass Spectrometry (AMS) at the Uppsala Tandem Labo- ratory. The 36Cl measurements in natural samples using a medium-sized tandem accelerator (∼1 MeV/amu) have been considered. A gas-filled magnetic spectrometer (GFM) was proposed for the separation of 36Cl from its isobar, 36S. Semi-empirical Monte-Carlo ion optical calculations were conducted to define optimal conditions for separating 36Cl and 36S. A 180° GFM was constructed and installed at the dedicated AMS beam line. 129I has been measured in waters from the Arctic and North Atlantic Oceans. Most of the 129I currently present in the Earth’s surface environment can be traced back to liquid and gaseous releases from the nuclear reprocessing facilities at Sellafield (UK) and La Hague (France).
    [Show full text]
  • Technical and Regulatory Guidance Environmental Molecular Diagnostics
    Technical and Regulatory Guidance Environmental Molecular Diagnostics New Site Characterization and Remediation Enhancement Tools April 2013 Prepared by The Interstate Technology & Regulatory Council Environmental Molecular Diagnostics Team ABOUT ITRC The Interstate Technology and Regulatory Council (ITRC) is a public-private coalition working to reduce bar- riers to the use of innovative environmental technologies and approaches so that compliance costs are reduced and cleanup efficacy is maximized. ITRC produces documents and training that broaden and deepen technical knowledge and expedite quality regulatory decision making while protecting human health and the envir- onment. With private and public sector members from all 50 states and the District of Columbia, ITRC truly provides a national perspective. More information on ITRC is available at www.itrcweb.org. ITRC is a pro- gram of the Environmental Research Institute of the States (ERIS), a 501(c)(3) organization incorporated in the District of Columbia and managed by the Environmental Council of the States (ECOS). ECOS is the national, nonprofit, nonpartisan association representing the state and territorial environmental commissioners. Its mission is to serve as a champion for states; to provide a clearinghouse of information for state envir- onmental commissioners; to promote coordination in environmental management; and to articulate state pos- itions on environmental issues to Congress, federal agencies, and the public. DISCLAIMER This material was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any war- ranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or use- fulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.
    [Show full text]
  • The Isotope Effect: Prediction, Discussion, and Discovery
    1 The isotope effect: Prediction, discussion, and discovery Helge Kragh Centre for Science Studies, Department of Physics and Astronomy, Aarhus University, 8000 Aarhus, Denmark. ABSTRACT The precise position of a spectral line emitted by an atomic system depends on the mass of the atomic nucleus and is therefore different for isotopes belonging to the same element. The possible presence of an isotope effect followed from Bohr’s atomic theory of 1913, but it took several years before it was confirmed experimentally. Its early history involves the childhood not only of the quantum atom, but also of the concept of isotopy. Bohr’s prediction of the isotope effect was apparently at odds with early attempts to distinguish between isotopes by means of their optical spectra. However, in 1920 the effect was discovered in HCl molecules, which gave rise to a fruitful development in molecular spectroscopy. The first detection of an atomic isotope effect was no less important, as it was by this means that the heavy hydrogen isotope deuterium was discovered in 1932. The early development of isotope spectroscopy illustrates the complex relationship between theory and experiment, and is also instructive with regard to the concepts of prediction and discovery. Keywords: isotopes; spectroscopy; Bohr model; atomic theory; deuterium. 1. Introduction The wavelength of a spectral line arising from an excited atom or molecule depends slightly on the isotopic composition, hence on the mass, of the atomic system. The phenomenon is often called the “isotope effect,” although E-mail: [email protected]. 2 the name is also used in other meanings.
    [Show full text]
  • Chapter 3 Exam Review KEY
    Chapter 3 Exam Review KEY I. Atomic Theory 1. Explain the law of conservation of mass in your own words. F I V E MOD ELS OF T H E ATOM Matter is neither created nor destroyed in a chemical reaction. 2. What were Rutherford’s two main conclusions about the structure of the atom? List the piece of evidence NUCLEAR MODEL: The atom can be SOthatLID SP supportsHERE MODE EACHL: The conclusion.atom is a divided into a nucleus and electrons. The solid sphere that cannot be divided up into nucleus occupies a small amount of space at smaller particles or pieces. the center of the atom. The nucleus is dense Evidence: Most of the α-particles passed right through the gold foil without deflection. and positively charged. The electrons circle around the nucleus. The electrons are tiny Conclusion: Most of an atom is composed of empty space. and negatively charged. Most of the atom is empty space. Evidence: Some were deflected somewhat, fewer were greatly deflected, and a very few Negative bounced back toward the source. electron Positive Conclusion: There is a dense positive nucleus. nucleus 3. Draw and describeLBCTCM_01_037 the atom model of each of the following scientists. a. Dalton PROTON MODEL: The atom can be divided PLUM PUDDING MODEL: The atomDalton can thought the atom was a solid sphere that was indivisible. into a nucleus and electrons. The nucleus be divided into a fluid (the “pudding”) and occupies a small amount of space at the electrons (the “plums”). The fluid spreads The Atomic Model Through Time center of theLBCTCM_01_036 atom.
    [Show full text]
  • I Can Describe an Atom and Its Components I Can Relate Energy
    Matter, part 2 ● I can describe an atom and its components ● I can relate energy levels of atoms to the chemical properties of elements ● I can define the concept of isotopes Isotopes ● Atoms of the same element that have different mass numbers ○ All atoms of the same element have the same number of protons ○ The number of neutrons can vary ○ ex)Chlorine atoms have 17 protons but can have 18 or 20 neutrons. ■ There are chlorine atoms with mass #s of 35 and 37. (17+18=35, 17+20=37) Isotopes ● Atomic mass- the average of the mass numbers of the isotopes of an element. ○ Most elements are mixtures of isotopes ○ ex) Atomic mass of chlorine is 35.453, the average of the mass numbers of naturally occurring isotopes of chlorine-35 and chlorine-37 Radioactive Isotopes ● Some isotopes are unstable and tend to break down ○ The isotope emits energy in the form of radiation ● The spontaneous process through which unstable nuclei emit radiation is called radioactive decay. Radioactive Isotopes ● In radioactive decay, a nucleus can... ○ lose protons and neutrons ○ change a proton to a neutron ○ change a neutron to a proton ● Because the # of protons identifies an element, decay changes the identity of the element Electron Energy Levels ● The exact position of an electron cannot be determined ○ Electrons occupy areas called energy levels ● The volume of an atom is mostly empty space ● The size of an atom depends on the number and arrangement of its electrons Electron Energy Levels ● The first energy level can hold 2 electrons ● The second energy level can hold 8 electrons ● The third energy level can hold 18 electrons ● The fourth energy level can hold 32 electrons.
    [Show full text]
  • FRACTIONATION of STABLE CHLORINE ISOTOPES DURING TRANSPORT THROUGH SEMIPERMEABLE MEMBRANES by Darcy Jo Campbell a Thesis Submitt
    Fractionation of stable chlorine isotopes during transport through semipermeable membranes Item Type Thesis-Reproduction (electronic); text Authors Campbell, Darcy Jo. Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 26/09/2021 22:51:29 Link to Item http://hdl.handle.net/10150/191280 FRACTIONATION OF STABLE CHLORINE ISOTOPES DURING TRANSPORT THROUGH SEMIPERMEABLE MEMBRANES by Darcy Jo Campbell A Thesis Submitted to the Faculty of the DEPARTMENT OF HYDROLOGY AND WATER RESOURCES In Partial Fulfillment of the Requirements For the Degree of MASTER OF SCIENCE WITH A MAJOR IN HYDROLOGY In the Graduate College THE UNIVERSITY OF ARIZONA 1985 STATEMENT BY AUTHOR This thesis has been submitted in partial fulfillment of re- quirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author.
    [Show full text]
  • GROUP 7 Halogen the Group of Halogens Is the Only Periodic Table
    GROUP 7 Halogen The group of halogens is the only periodic table group that contains elements in all three familiar states of matter at standard temperature and pressure. All of the halogens form acids when bonded to hydrogen. Most halogens are typically produced from minerals of salts. The middle halogens, that is, chlorine, bromine and iodine, are often used as disinfectants. The halogens are also all toxic. Characteristics Chemical The halogens show trends in chemical bond energy moving from top to bottom of the periodic table column with fluorine deviating slightly. (It follows trend in having the highest bond energy in compounds with other atoms, but it has very weak bonds within the diatomic F2 element molecules.) Halogen bond energies (kJ/mol)[4] X X2 HX BX3 AlX3 CX4 F 159 574 645 582 456 Cl 243 428 444 427 327 Br 193 363 368 360 272 1 I 151 294 272 285 239 Halogens are highly reactive, and as such can be harmful or lethal to biological organisms in sufficient quantities. This high reactivity is due to the high electronegativity of the atoms due to their high effective nuclear charge. They can gain an electron by reacting with atoms of other elements. Fluorine is one of the most reactive elements in existence, attacking otherwise-inert materials such as glass, and forming compounds with the heavier noble gases. It is a corrosive and highly toxic gas. The reactivity of fluorine is such that, if used or stored in laboratory glassware, it can react with glass in the presence of small amounts of water to form silicon tetrafluoride (SiF4).
    [Show full text]
  • 4.3 Distinguishing Among Atoms > Chapter 4
    4.3 Distinguishing Among Atoms > Chapter 4 Atomic Structure 4.1 Defining the Atom 4.2 Structure of the Nuclear Atom 4.3 Distinguishing Among Atoms 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 4.3 Distinguishing Among Atoms > CHEMISTRY & YOU How can there be different varieties of atoms? Just as there are many types of dogs, atoms come in different varieties too. 2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 4.3 Distinguishing Among Atoms > Atomic Number and Mass Number Atomic Number and Mass Number • What makes one element different from another? 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 4.3 Distinguishing Among Atoms > Atomic Number and Mass Number Atomic Number • Elements are different because they contain different numbers of protons. • An element’s atomic number is the number of protons in the nucleus of an atom of that element. • The atomic number identifies an element. 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 4.3 Distinguishing Among Atoms > Interpret Data For each element listed in the table below, the number of protons equals the number of electrons. Atoms of the First Ten Elements Name Symbol Atomic Protons Neutrons Mass Electrons number number Hydrogen H 1 1 0 1 1 Helium He 2 2 2 4 2 Lithium Li 3 3 4 7 3 Beryllium Be 4 4 5 9 4 Boron B 5 5 6 11 5 Carbon C 6 6 6 12 6 Nitrogen N 7 7 7 14 7 Oxygen O 8 8 8 16 8 Fluorine F 9 9 10 19 9 Neon Ne 10 10 10 20 10 5 Copyright © Pearson Education, Inc., or its affiliates.
    [Show full text]
  • Symbols of Elements
    The Atom Atomic Number and Mass Number Isotopes LecturePLUS Timberlake 1 Atomic Theory Atoms are building blocks of elements Similar atoms in each element Different from atoms of other elements Two or more different atoms bond in simple ratios to form compounds LecturePLUS Timberlake 2 Subatomic Particles Particle Symbol Charge Relative Mass Electron e- 1- 0 Proton p+ + 1 Neutron n 0 1 LecturePLUS Timberlake 3 Location of Subatomic Particles -13 10 cm electrons protons nucleus neutrons -8 10 cm LecturePLUS Timberlake 4 Atomic Number Counts the number of protons in an atom LecturePLUS Timberlake 5 Periodic Table Represents physical and chemical behavior of elements Arranges elements by increasing atomic number Repeats similar properties in columns known as chemical families or groups LecturePLUS Timberlake 6 Periodic Table 1 2 3 4 5 6 7 8 11 Na LecturePLUS Timberlake 7 Atomic Number on the Periodic Table Atomic Number 11 Symbol Na LecturePLUS Timberlake 8 All atoms of an element have the same number of protons 11 protons 11 Sodium Na LecturePLUS Timberlake 9 Learning Check AT 1 State the number of protons for atoms of each of the following: A. Nitrogen 1) 5 protons 2) 7 protons 3) 14 protons B. Sulfur 1) 32 protons 2) 16 protons 3) 6 protons C. Barium 1) 137 protons 2) 81 protons 3) 56 protons LecturePLUS Timberlake 10 Solution AT 1 State the number of protons for atoms of each of the following: A. Nitrogen 2) 7 protons B. Sulfur 2) 16 protons C. Barium 3) 56 protons LecturePLUS Timberlake 11 Number of Electrons An atom is neutral
    [Show full text]
  • SL Topic 2 Questions 1. Consider the Composition of the Species W, X, Y
    IB Chemistry – SL Topic 2 Questions 1. Consider the composition of the species W, X, Y and Z below. Which species is an anion? Species Number of protons Number of neutrons Number of electrons W 9 10 10 X 11 12 11 Y 12 12 12 Z 13 14 10 A. W B. X C. Y D. Z (Total 1 mark) 2. Energy levels for an electron in a hydrogen atom are A. evenly spaced. B. farther apart near the nucleus. C. closer together near the nucleus. D. arranged randomly. (Total 1 mark) 3. Which is related to the number of electrons in the outer main energy level of the elements from the alkali metals to the halogens? I. Group number II. Period number A. I only B. II only C. Both I and II D. Neither I nor II (Total 1 mark) 4. How do bond length and bond strength change as the number of bonds between two atoms Page 1 of 19 increases? Bond length Bond strength A. Increases increases B. Increases decreases C. Decreases increases D. Decreases decreases (Total 1 mark) 5. Which of the following is true for CO2? C O bond CO2 molecule A. Polar non-polar B. non-polar polar C. Polar polar D. non-polar non-polar (Total 1 mark) 6. The molar masses of C2H6, CH3OH and CH3F are very similar. How do their boiling points compare? A. C2H6 < CH3OH < CH3F B. CH3F < CH3OH < C2H6 C. CH3OH < CH3F < C2H6 D. C2H6 < CH3F < CH3OH (Total 1 mark) 7. What is the correct number of each particle in a fluoride ion, 19F–? protons neutrons electrons A.
    [Show full text]