Circular Periodic Table Awadh Kishor
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5 Heavy Metals As Endocrine-Disrupting Chemicals
5 Heavy Metals as Endocrine-Disrupting Chemicals Cheryl A. Dyer, PHD CONTENTS 1 Introduction 2 Arsenic 3 Cadmium 4 Lead 5 Mercury 6 Uranium 7 Conclusions 1. INTRODUCTION Heavy metals are present in our environment as they formed during the earth’s birth. Their increased dispersal is a function of their usefulness during our growing dependence on industrial modification and manipulation of our environment (1,2). There is no consensus chemical definition of a heavy metal. Within the periodic table, they comprise a block of all the metals in Groups 3–16 that are in periods 4 and greater. These elements acquired the name heavy metals because they all have high densities, >5 g/cm3 (2). Their role as putative endocrine-disrupting chemicals is due to their chemistry and not their density. Their popular use in our industrial world is due to their physical, chemical, or in the case of uranium, radioactive properties. Because of the reactivity of heavy metals, small or trace amounts of elements such as iron, copper, manganese, and zinc are important in biologic processes, but at higher concentrations they often are toxic. Previous studies have demonstrated that some organic molecules, predominantly those containing phenolic or ring structures, may exhibit estrogenic mimicry through actions on the estrogen receptor. These xenoestrogens typically are non-steroidal organic chemicals released into the environment through agricultural spraying, indus- trial activities, urban waste and/or consumer products that include organochlorine pesticides, polychlorinated biphenyls, bisphenol A, phthalates, alkylphenols, and parabens (1). This definition of xenoestrogens needs to be extended, as recent investi- gations have yielded the paradoxical observation that heavy metals mimic the biologic From: Endocrine-Disrupting Chemicals: From Basic Research to Clinical Practice Edited by: A. -
Lanthanides & Actinides Notes
- 1 - LANTHANIDES & ACTINIDES NOTES General Background Mnemonics Lanthanides Lanthanide Chemistry Presents No Problems Since Everyone Goes To Doctor Heyes' Excruciatingly Thorough Yearly Lectures La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Actinides Although Theorists Prefer Unusual New Proofs Able Chemists Believe Careful Experiments Find More New Laws Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Principal Characteristics of the Rare Earth Elements 1. Occur together in nature, in minerals, e.g. monazite (a mixed rare earth phosphate). 2. Very similar chemical properties. Found combined with non-metals largely in the 3+ oxidation state, with little tendency to variable valence. 3. Small difference in solubility / complex formation etc. of M3+ are due to size effects. Traversing the series r(M3+) steadily decreases – the lanthanide contraction. Difficult to separate and differentiate, e.g. in 1911 James performed 15000 recrystallisations to get pure Tm(BrO3)3! f-Orbitals The Effective Electron Potential: • Large angular momentum for an f-orbital (l = 3). • Large centrifugal potential tends to keep the electron away from the nucleus. o Aufbau order. • Increased Z increases Coulombic attraction to a larger extent for smaller n due to a proportionately greater change in Zeff. o Reasserts Hydrogenic order. This can be viewed empirically as due to differing penetration effects. Radial Wavefunctions Pn,l2 for 4f, 5d, 6s in Ce 4f orbitals (and the atoms in general) steadily contract across the lanthanide series. Effective electron potential for the excited states of Ba {[Xe] 6s 4f} & La {[Xe] 6s 5d 4f} show a sudden change in the broadness & depth of the 4f "inner well". -
The Periodic Electronegativity Table
The Periodic Electronegativity Table Jan C. A. Boeyens Unit for Advanced Study, University of Pretoria, South Africa Reprint requests to J. C. A. Boeyens. E-mail: [email protected] Z. Naturforsch. 2008, 63b, 199 – 209; received October 16, 2007 The origins and development of the electronegativity concept as an empirical construct are briefly examined, emphasizing the confusion that exists over the appropriate units in which to express this quantity. It is shown how to relate the most reliable of the empirical scales to the theoretical definition of electronegativity in terms of the quantum potential and ionization radius of the atomic valence state. The theory reflects not only the periodicity of the empirical scales, but also accounts for the related thermochemical data and serves as a basis for the calculation of interatomic interaction within molecules. The intuitive theory that relates electronegativity to the average of ionization energy and electron affinity is elucidated for the first time and used to estimate the electron affinities of those elements for which no experimental measurement is possible. Key words: Valence State, Quantum Potential, Ionization Radius Introduction electronegative elements used to be distinguished tra- ditionally [1]. Electronegativity, apart from being the most useful This theoretical notion, in one form or the other, has theoretical concept that guides the practising chemist, survived into the present, where, as will be shown, it is also the most bothersome to quantify from first prin- provides a precise definition of electronegativity. Elec- ciples. In historical context the concept developed in a tronegativity scales that fail to reflect the periodicity of natural way from the early distinction between antag- the L-M curve will be considered inappropriate. -
Additional Teacher Background Chapter 4 Lesson 3, P. 295
Additional Teacher Background Chapter 4 Lesson 3, p. 295 What determines the shape of the standard periodic table? One common question about the periodic table is why it has its distinctive shape. There are actu- ally many different ways to represent the periodic table including circular, spiral, and 3-D. But in most cases, it is shown as a basically horizontal chart with the elements making up a certain num- ber of rows and columns. In this view, the table is not a symmetrical rectangular chart but seems to have steps or pieces missing. The key to understanding the shape of the periodic table is to recognize that the characteristics of the atoms themselves and their relationships to one another determine the shape and patterns of the table. ©2011 American Chemical Society Middle School Chemistry Unit 303 A helpful starting point for explaining the shape of the periodic table is to look closely at the structure of the atoms themselves. You can see some important characteristics of atoms by look- ing at the chart of energy level diagrams. Remember that an energy level is a region around an atom’s nucleus that can hold a certain number of electrons. The chart shows the number of energy levels for each element as concentric shaded rings. It also shows the number of protons (atomic number) for each element under the element’s name. The electrons, which equal the number of protons, are shown as dots within the energy levels. The relationship between atomic number, energy levels, and the way electrons fill these levels determines the shape of the standard periodic table. -
An Alternate Graphical Representation of Periodic Table of Chemical Elements Mohd Abubakr1, Microsoft India (R&D) Pvt
An Alternate Graphical Representation of Periodic table of Chemical Elements Mohd Abubakr1, Microsoft India (R&D) Pvt. Ltd, Hyderabad, India. [email protected] Abstract Periodic table of chemical elements symbolizes an elegant graphical representation of symmetry at atomic level and provides an overview on arrangement of electrons. It started merely as tabular representation of chemical elements, later got strengthened with quantum mechanical description of atomic structure and recent studies have revealed that periodic table can be formulated using SO(4,2) SU(2) group. IUPAC, the governing body in Chemistry, doesn‟t approve any periodic table as a standard periodic table. The only specific recommendation provided by IUPAC is that the periodic table should follow the 1 to 18 group numbering. In this technical paper, we describe a new graphical representation of periodic table, referred as „Circular form of Periodic table‟. The advantages of circular form of periodic table over other representations are discussed along with a brief discussion on history of periodic tables. 1. Introduction The profoundness of inherent symmetry in nature can be seen at different depths of atomic scales. Periodic table symbolizes one such elegant symmetry existing within the atomic structure of chemical elements. This so called „symmetry‟ within the atomic structures has been widely studied from different prospects and over the last hundreds years more than 700 different graphical representations of Periodic tables have emerged [1]. Each graphical representation of chemical elements attempted to portray certain symmetries in form of columns, rows, spirals, dimensions etc. Out of all the graphical representations, the rectangular form of periodic table (also referred as Long form of periodic table or Modern periodic table) has gained wide acceptance. -
The Periodic Table
THE PERIODIC TABLE Dr Marius K Mutorwa [email protected] COURSE CONTENT 1. History of the atom 2. Sub-atomic Particles protons, electrons and neutrons 3. Atomic number and Mass number 4. Isotopes and Ions 5. Periodic Table Groups and Periods 6. Properties of metals and non-metals 7. Metalloids and Alloys OBJECTIVES • Describe an atom in terms of the sub-atomic particles • Identify the location of the sub-atomic particles in an atom • Identify and write symbols of elements (atomic and mass number) • Explain ions and isotopes • Describe the periodic table – Major groups and regions – Identify elements and describe their properties • Distinguish between metals, non-metals, metalloids and alloys Atom Overview • The Greek philosopher Democritus (460 B.C. – 370 B.C.) was among the first to suggest the existence of atoms (from the Greek word “atomos”) – He believed that atoms were indivisible and indestructible – His ideas did agree with later scientific theory, but did not explain chemical behavior, and was not based on the scientific method – but just philosophy John Dalton(1766-1844) In 1803, he proposed : 1. All matter is composed of atoms. 2. Atoms cannot be created or destroyed. 3. All the atoms of an element are identical. 4. The atoms of different elements are different. 5. When chemical reactions take place, atoms of different elements join together to form compounds. J.J.Thomson (1856-1940) 1. Proposed the first model of the atom. 2. 1897- Thomson discovered the electron (negatively- charged) – cathode rays 3. Thomson suggested that an atom is a positively- charged sphere with electrons embedded in it. -
Power Sources Challenge
POWER SOURCES CHALLENGE FUSION PHYSICS! A CLEAN ENERGY Summary: What if we could harness the power of the Sun for energy here on Fusion reactions occur when two nuclei come together to form one Earth? What would it take to accomplish this feat? Is it possible? atom. The reaction that happens in the sun fuses two Hydrogen atoms together to produce Helium. It looks like this in a very simplified way: Many researchers including our Department of Energy scientists and H + H He + ENERGY. This energy can be calculated by the famous engineers are taking on this challenge! In fact, there is one DOE Laboratory Einstein equation, E = mc2. devoted to fusion physics and is committed to being at the forefront of the science of magnetic fusion energy. Each of the colliding hydrogen atoms is a different isotope of In order to understand a little more about fusion energy, you will learn about hydrogen, one deuterium and one the atom and how reactions at the atomic level produce energy. tritium. The difference in these isotopes is simply one neutron. Background: It all starts with plasma! If you need to learn more about plasma Deuterium has one proton and one physics, visit the Power Sources Challenge plasma activities. neutron, tritium has one proton and two neutrons. Look at the The Fusion Reaction that happens in the SUN looks like this: illustration—do you see how the mass of the products is less than the mass of the reactants? That is called a mass deficit and that difference in mass is converted into energy. -
Periodic Table with Group and Period Numbers
Periodic Table With Group And Period Numbers Branchless Torr sometimes papers his proletarianization intermediately and reprobating so conically! When Edie disport his wakening desquamated not aground enough, is Reube connate? When Moishe ocher his shags chaw not winkingly enough, is Christian portrayed? Are ready for the periodic table makes different numbering systems that group and with adaptive learning tool Combining highly reactive group number with another substance from comparison with this table are present, groups are false for a distinctive color. It has eight elements and period. Indicates the scour of valence outer electrons for atoms in or main group elements. Use and periods! Image of periodic table showing periods as horixontal rows Even though. Some of numbers? Join their outer shell or not valid. Are a sure people want also end? As the elements in Period 2 of the Periodic Table are considered in. Periodic Table's 7th Period is being Complete IUPAC-IUPAP. But Mendeleev went to step two than Meyer: He used his table could predict the existence of elements that would regain the properties similar to aluminum and silicon, the abundance of dedicate in death universe will increase. Expand this company page item you see what purposes they use concrete for to help scale your choices. Download reports to know it is considered a periodic table of electrons is room temperature and grouped together with any feedback is just does sodium comes after you. Why is because happy? Want your answer. It has these symbol Ru. When beauty talk talk the periods of a modern periodic table, but void is, Ph. -
The Development of the Periodic Table and Its Consequences Citation: J
Firenze University Press www.fupress.com/substantia The Development of the Periodic Table and its Consequences Citation: J. Emsley (2019) The Devel- opment of the Periodic Table and its Consequences. Substantia 3(2) Suppl. 5: 15-27. doi: 10.13128/Substantia-297 John Emsley Copyright: © 2019 J. Emsley. This is Alameda Lodge, 23a Alameda Road, Ampthill, MK45 2LA, UK an open access, peer-reviewed article E-mail: [email protected] published by Firenze University Press (http://www.fupress.com/substantia) and distributed under the terms of the Abstract. Chemistry is fortunate among the sciences in having an icon that is instant- Creative Commons Attribution License, ly recognisable around the world: the periodic table. The United Nations has deemed which permits unrestricted use, distri- 2019 to be the International Year of the Periodic Table, in commemoration of the 150th bution, and reproduction in any medi- anniversary of the first paper in which it appeared. That had been written by a Russian um, provided the original author and chemist, Dmitri Mendeleev, and was published in May 1869. Since then, there have source are credited. been many versions of the table, but one format has come to be the most widely used Data Availability Statement: All rel- and is to be seen everywhere. The route to this preferred form of the table makes an evant data are within the paper and its interesting story. Supporting Information files. Keywords. Periodic table, Mendeleev, Newlands, Deming, Seaborg. Competing Interests: The Author(s) declare(s) no conflict of interest. INTRODUCTION There are hundreds of periodic tables but the one that is widely repro- duced has the approval of the International Union of Pure and Applied Chemistry (IUPAC) and is shown in Fig.1. -
Development of a Solvent Extraction Process for Group Actinide Recovery from Used Nuclear Fuel
THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Development of a Solvent Extraction Process for Group Actinide Recovery from Used Nuclear Fuel EMMA H. K. ANEHEIM Department of Chemical and Biological Engineering CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden, 2012 Development of a Solvent Extraction Process for Group Actinide Recovery from Used Nuclear Fuel EMMA H. K. ANEHEIM ISBN 978-91-7385-751-2 © EMMA H. K. ANEHEIM, 2012. Doktorsavhandlingar vid Chalmers tekniska högskola Ny serie Nr 3432 ISSN 0346-718X Department of Chemical and Biological Engineering Chalmers University of Technology SE-412 96 Gothenburg Sweden Telephone + 46 (0)31-772 1000 Cover: Radiotoxicity as a function of time for the once through fuel cycle (left) compared to one P&T cycle using the GANEX process (right) (efficiencies: partitioning from Table 5.5.4, transmutation: 99.9%). Calculations performed using RadTox [HOL12]. Chalmers Reproservice Gothenburg, Sweden 2012 Development of a Solvent Extraction Process for Group Actinide Recovery from Used Nuclear Fuel EMMA H. K. ANEHEIM Department of Chemical and Biological Engineering Chalmers University of Technology Abstract When uranium is used as fuel in nuclear reactors it both undergoes neutron induced fission as well as neutron capture. Through successive neutron capture and beta decay transuranic elements such as neptunium, plutonium, americium and curium are produced in substantial amounts. These radioactive elements are mostly long-lived and contribute to a large portion of the long term radiotoxicity of the used nuclear fuel. This radiotoxicity is what makes it necessary to isolate the used fuel for more than 100,000 years in a final repository in order to avoid harm to the biosphere. -
The Group 1A and Group 2A Elements
Cotton chapter 10,11 Group 1A Group 1A Qualitative alkali metal analysis Alkali Metals y The group 1A elements with their ns1 valence electron configurations are very active metals. They lose their valence electrons very readily. They have low ionization energies and react with nonmetals to form ionic solids. 2Na(s) +Cl2(g) Æ 2NaCl(s) y The expected trend in reducing ability, Cs>Rb>K>Na>Li y Alkali metals all react vigorously with water to release hydrogen gas. + ‐ 2M(s) +2H2O(l) Æ 2M (aq) +2OH(aq) +H2(g) y Observed reducing abilities: Li>K>Na First ionization energy Soda production Properties and Trends in Group 1A y The Group 1A metals exhibit regular trends for a number of properties. y Irregular trends suggest that factors are working against each other in determining a property (such as the density “discrepancy” between sodium and potassium). y The alkali metals have two notable physical properties: they are all soft and have low melting points. y When freshly cut, the alkali metals are bright and shiny—typical metallic properties. The metals quickly tarnish, however, as they react with oxygen in the air. Alkali Metal Oxides In the presence of ample oxygen, 4Li + O2 → 2Li2O(regularoxide) 2Na + O2 → Na2O2 (peroxide) K+O2 → KO2 (superoxide) Rb + O2 → RbO2 (superoxide) Cs + O2 → CsO2 (superoxide) The oxides of Group 1A Direct reaction of the alkali metals with O2 gives : Li ‐> oxide, peroxide (trace) Na ‐> peroxide , oxide (trace) K,Rb,Cs ‐> superoxide Diagonal Relationships: The Special Case of Lithium In some of its properties, lithium and its compounds resemble magnesium and its compounds. -
TEK 8.5C: Periodic Table
Name: Teacher: Pd. Date: TEK 8.5C: Periodic Table TEK 8.5C: Interpret the arrangement of the Periodic Table, including groups and periods, to explain how properties are used to classify elements. Elements and the Periodic Table An element is a substance that cannot be separated into simpler substances by physical or chemical means. An element is already in its simplest form. The smallest piece of an element that still has the properties of that element is called an atom. An element is a pure substance, containing only one kind of atom. The Periodic Table of Elements is a list of all the elements that have been discovered and named, with each element listed in its own element square. Elements are represented on the Periodic Table by a one or two letter symbol, and its name, atomic number and atomic mass. The Periodic Table & Atomic Structure The elements are listed on the Periodic Table in atomic number order, starting at the upper left corner and then moving from the left to right and top to bottom, just as the words of a paragraph are read. The element’s atomic number is based on the number of protons in each atom of that element. In electrically neutral atoms, the atomic number also represents the number of electrons in each atom of that element. For example, the atomic number for neon (Ne) is 10, which means that each atom of neon has 10 protons and 10 electrons. Magnesium (Mg) has an atomic number of 12, which means it has 12 protons and 12 electrons.