DOCSLIB.ORG

Atomic Structure; Isotopes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

CHEMISTRY 103 – Help Sheet #2 Atoms, Molecules, and Ions Do the topics appropriate for your course Prepared by Dr. Tony Jacob https://clc.chem.wisc.edu (Resources page) Nuggets: Atomic structure; Isotopes; Counting neutrons, protons, electrons; Average Atomic Mass; Mass Spectroscopy (Part I); Ionic vs molecular compounds; Naming chemicals; Writing formulas from names; Polyatomic ions; Coulomb’s law ATOMIC STRUCTURE Rutherford's Au Foil Experiment: Mass of atom is concentrated in a highly dense nucleus that was positively charged; the rest of the atom has only a small amount of mass; alpha particles are positively charged so they are repelled by the nucleus comprised of protons (positively charged) and are small compared to the size of the atom allowing them to pass through the atom Nucleus: contains nearly all the atom’s mass; neutrons and protons located in the nucleus and the nucleus is a very small volume of the atom; extremely dense; atom is mostly empty space Elements: determined by the number of protons they contain Masses of all atoms are compared to 12C which is the standard reference; 12C is defined as 12.0000... atomic mass units (exact value) = 12.0000...amu; (amu = atomic mass units) 1 23 -24 1 amu = /6.022 x 10 = 1.6605 x 10 g Neutron (n): has a neutral charge; mass ≈ 1amu ≈ 1 x 10-24g (1.6749 x 10-24g) Proton (p+): has a charge of +1; mass ≈ 1amu ≈ 1 x 10-24g (1.6726 x 10-24g) Electron (e-): has a charge of -1; mass ≈ 0.0005amu ≈ 1 x 10-27g (9.1094 x 10-28g) Relative masses: n > p+ >> e-; mass of n ≈ p+ ≈ 1 with e- ≈ 1/2000 ISOTOPES: elements with the same #p+ (same element) but different #n (different mass) A + + Isotope Symbol: ZElement Symbol A = mass number = #p + #n; Z = atomic number = #p 12 13 14 + C isotopes: 6C , 6C , and 6C; the 3 isotopes of C each have Z = 6 (6p ) but different #n (6, 7, and 8) Example 1: What is mass of one atom of 16O-2 in kg? ⎛ −24 ⎞ -26 16 -2 16 -2 16 −2 1.6605 x 10 g ⎛ 1kg ⎞ −26 Answer 1:€ 2.7 x 10 kg { O = 16amu; mass of 1 atom O = 16u; O = 16amu⎜ ⎟ ⎜ ⎟ = 2.6568 x 10 kg } € € € ⎝⎜ 1amu ⎠⎟ ⎝ 1000g⎠ AVERAGE ATOMIC MASS (AAM): weighted average of all isotopes of one element taking into account the abundance of each isotope; units = amu; e.g., average atomic mass Br = 79.90amu Abundance: percent of one isotope as compared to all atoms of that given element AVERAGE ATOMIC MASS (AAM) = S(mass of isotope) x (fractional abundance) AAM = (massiso1)(fractional abundanceiso1) + (massiso2)(fractional abundanceiso2) + … = AAM = (M1)(FA1) + (M2)(FA2) + … Sum of fractional abundances = 1 (i.e., 100%); for elements with only 2 isotopes: FA1 + FA2 = 1 Example 2: Calculate the average atomic mass of an element given following data: isotope 1: 27.977amu, 92.21% abundance; isotope 2: 28.976amu, 4.70% abundance; and isotope 3: 29.974amu, 3.09% abundance. Answer 2: 28.09amu {AAM = (M1)(FA1) + (M2)(FA2) + (M3)(FA3) = (27.977)(0.9221) + (28.976)(0.0470) + (29.974)(0.0309) = 28.09amu} Example 3: What are the abundances of the 2 B isotopes (10B mass = 10.0129u, 11B mass = 11.0093u), if the average atomic mass of B is 10.811amu? Answer 3: 10B = 19.90% and 11B = 80.10% AAM = (M1)(FA1) + (M2)(FA2); 10.811 = 10.0129x + 11.0093y; since there are 2 unknowns 2 equations are needed; second equation: FA1 + FA2 = 1 (which is 100%); x + y = 1 ® y = 1 - x; substitute this into the first equation: 10.811 = 10.0129x + 11.0093(1-x); solve for x: 10.811 = 10.0129x +11.0093 – 11.0093x; 0.1983 = 0.9964x; x = 0.1990 = 19.90%; y = 1-x = 1-0.1990 = 0.8010 = 80.10%; since x was the abundance for 10B ® abundance of 10B = 19.90% and abundance of 11B = y = 80.10%} MASS SPECTROSCOPY: single atoms experimental technique that yields a plot called a mass spectrum of mass to charge ratio, (m/z), versus abundance (or intensity); see the class video M2Q3 for a wonderful description of a mass spectrometer Example 4: Mg has 3 isotopes: 24Mg (79% abundance), 25Mg (10% abundance), 26Mg (11% abundance). Draw the mass spectRum foR this element? 79% Mg 10% Abundance Intensity or 11% 10 20 30 40 24 25 26 Answer 4: m/z MASS SPECTROSCOPY: compounds (Not all instructors will be covering mass spectroscopy of compounds; instructors will be covering mass spectroscopy of single atom elements or molecules like Br2, Cl2, etc., but some sections may not cover compounds like C2H6O.) Hard Mass Spectroscopy: This technique breaks the molecule into individual atoms Soft Mass Spectroscopy: This technique ionizes the molecule and the one peak shown represents the molar mass of the molecule (molar mass is the sum of the average atomic mass of the individual elements within the molecule; e.g., for C3H6O1 the molar mass = 3(mass of C) + 6(mass of H) + 1(mass of O) = 3(12) + 6(1) +1(16) = 58g/mol; this will be revisited in HelpSheet #4!) Empirical formula: the simplest formula that shows the ratio between atoms within the compound (this will be revisited in HelpSheet #4!) Molecular formula: the actual formula of the compound; (e.g., molecular formula = N2O4 while the empirical formula = NO2; i.e., the simplest ratio between N and O atoms in N2O4) Example 5: A chemical compound was analyzed by mass spectroscopy and both “hard” and “soft” mass spectra were obtained. a. What is the empirical formula for the unknown compound? b. What is the molecular formula for the unknown compound? Hard MS Soft MS 100% 60.0% 30.0% Intensity or Abundance Intensity or 10.0% Abundance Intensity or 1 12 16 116 m/z m/z Answer 5: a. empirical formula = C3H6O1 {from the hard mass spectrum (Hard MS) it can be determined that the compound contains H (mass = 1), C (mass = 12), and O (mass = 16). From the percent intensity or abundance the number of each element can be determined by dividing each element by the smallest percent; 10/0% in this example. 60% 30% 10% H = = 6 ; C = = 3 ; O = = 1 ; this yields an empirical formula = C H O } 10% 10% 10% 3 6 1 b. molecular formula = C6H12O2 {from the soft mass spectrum (Soft MS) the peak represents the compound’s molar mass; molar mass = 116g/mol; the empirical formula (C3H6O1) molar mass = 58g/mol [3(mass of C) + 6(mass of H) + 1(mass of O) = 3(12) + 6(1) +1(16) = 58g/mol] molar massmolecular formula 116g / mol to determine the molecular formula, determine ratio = ; ratio = = 2 ; molar massempiricalformula 58g / mol use the ratio just determined and multiply the empirical formula by 2: C(3 x 2)H(6 x 2)O(1 x 2) = C6H12O2} IONIC COMPOUNDS: contain metal + nonmetal (can substitute a polyatomic ion for eitheR or both) Properties: extended solids; not discrete molecules; high melting/boiling points; conducts electricity in molten state; Examples: NaCl(s), Ca(NO3)2(s), NH4NO3(s), AgCl(s) Name Formula - Ammonium + Ions: atoms or molecules that have lost/gained e (charges are not changed NH4 Hydronium + by gaining/losing protons!) H3O Cations: positively charged atoms (electrons have been lost) Hydroxide OH- Acetate - Anions: negatively charged atoms (electrons have been gained) CH3COO Polyatomic Ions: “many-atom ions”; these compounds are not broken up Nitrate - NO3 and are treated as a group: Permanganate - MnO4 Hydrogen Carbonate - HCO3 Charges on elements in Ionic Compounds based on the column of Periodic Carbonate -2 Table the element resides in: CO3 Hydrogen Sulfate - + + +2 +2 HSO4 Group IA: +1 (H , Li , ...) Group IIA: +2 (Be , Mg , ...) Sulfate -2 +3 +3 SO4 Group IIIA: +3 (B , Al , ...) Phosphate -3 -3 -3 -2 -2 PO4 Group VA: -3 (N , P , ...) Group VIA: -2 (O , S , ...) Group VIIA: -1 (F-, Cl-, ...) Naming • Metal + Nonmetal ® ionic compound; metal name followed by nonmetal “root”+"ide" Example 6: What is the name for CaCl2? ® Answer 6: calcium chloride (note: not dichloride!) • Contains one oR two Polyatomic Ions ® ionic compound; use polyatomic ion name Example 7: What is the name for Ca3(PO4)2? ® Answer 7: calcium phosphate (note: not tricalcium nor diphosphate!) Example 8: What is the name for (NH4)2SO4? ® Answer 8: ammonium sulfate (note: not diammonium!) • Contains Transition Metal ® ionic compound; metal name (charge in Roman numerals) Example 9: What is the name for Fe2(SO4)3? ® Answer 9: iron(III) sulfate (see below for process to follow) 1. Transition metals have charges that vary so the metal charge needs to be determined and specified in the name; the charge is written in Roman numerals in parentheses after the metal name -2 2. Find charge on Fe. First, SO4 charge is -2 (memorized); total negative charge: 3(-2) = -6 from the 3 SO4 ; since the compound is neutral the 2 Fe must total +6 ® therefore, each Fe = +3 = Fe+3; the Roman numeral for 3 = III IONIC COMPOUNDS (continued): Writing Formulas 1. Take metal name or polyatomic ion and write formula including charge • If metal has a Roman numeral, then charge is determined from that numeral (e.g., copper(II) = Cu+2) + • If it does not have a Roman numeral, it is a memorized polyatomic ion (e.g., ammonium = NH4 ) or determined from the column in the Periodic Table it resides in (e.g., magnesium = Mg+2 since it is in column IIA) 2. Take nonmetal name or polyatomic ion and write formula including charge • If nonmetal name ends with “ide” it is a single atom ion with a negative charge with the charge determined from column in Periodic Table it resides in (e.g., chloride = Cl- since column VIIA has a -1 charge); exceptions: hydroxide (OH-) and cyanide (CN-) are polyatomic ions with a name that ends in “ide” • If name ends with “ite” or “ate”, or starts with “hypo” or “per” it is a memorized polyatomic ion 3.
Recommended publications
  • CHEM 1A: Exam 1 Practice Problems

    CHEM 1A: Exam 1 Practice Problems

    CHEM 1A: Exam 1 Practice Problems: These practice problems are not a comprehensive list of all questions to be asked on the exam. Refer to the suggested textbook HW, other practice problems on the review page, iclicker questions, & challenge problem sets for a comprehensive review. Unit Conversions & Dimensional Analysis: 65.3 g of Iron → _______________ mol Iron 12 3.97 x 10 CO2 molecules →_______________ mol CO2 0.783 mol of CH3CH2OH →_______________ mL of CH3CH2OH Reference Information: Density = 0.789 g/mL The density of a sample of propane (C3H8) gas is 1.80 g/L. How many molecules of propane are contained in a 1.50 L balloon? What about the total number of atoms? 1.097 x 10-2 nm-1 → _______________ m-1 True or False: A gram of magnesium contains more atoms than a gram of calcium. Each conversion below involves at least one mistake. Can you identify the mistakes and correct them? Corrected Conversions: 5.98 푚표푙 1 퐿 1 푚퐿 푚표푙 = ? 퐿 10−3푚퐿 1 푐푚3 푐푚3 ________________________________________________________________________________________________________________________________________________________________________________________________________________________ 0.087 푛푚 1 푚 1 푚푚 = ? 푚푚 1 10−9푛푚 103푚 ________________________________________________________________________________________________________________________________________________________________________________________________________________________ 7.874 푔 1 푘푔 (10−2푐푚)3 푘푔 = ? 푐푚3 10−3푔 (1 푚)3 푚3 Nomenclature & Formulas Which of the following compounds contains the cation with the highest charge? CuCl2 BaCl2 Na3PO4 Fe(NO3)3 Complete the table below. Formula Name CaCl2 Calcium Chloride Mg3(PO4)2 Magnesium phosphate Co(MnO4)2 Cobalt (II) permanganate Fe2S3 Iron (III) Sulfide H2SO3 Sulfurous acid HClO Hypochlorous acid P4O10 Tetraphosphorus decoxide N2O5 Dinitrogen pentoxide Atomic Theory & Nuclear Chemistry Complete the table below.
  • Agenda 10/6/2017 Per 2. Isotope - One More Time

    Agenda 10/6/2017 Per 2. Isotope - One More Time

    Agenda 10/6/2017 Per 2. Isotope - one more time https://drive.google.com/drive/folders/0BzGRyLjDEz_XdFJrN2ZBNkM4TDg • Slip Quiz • Modern Model of the Atom • Limitations of Model 1 in Isotopes Pogil • Average Atomic Mass • Looking for Patterns - Analysis Activity • Homework Slip Quiz 1.How many neutrons in an atom of neon-21 (21Ne). State clearly how you figure it out. 2. How many electrons in a neon-21 atom? How do you know? Slip Quiz 1.How many neutrons in an atom of neon-21 (21Ne). State how you know. I find neon’s atomic number on periodic table, neon has atomic number 10 which tells me it has 10 protons in its nucleus. The remainder of the particles in the nucleus are neutrons. Mass number - atomic number = number of neutrons 21 - 10 = 11 So Ne-21 has 11 neutrons. Slip Quiz 2. How many electrons in a neon-21 atom? How do you know? I know that for an electrically neutral atom, the number of protons in the nucleus is equal to the number of electrons in the electron cloud around the nucleus. For question 1 I found the atomic number of neon-21 is 10, hence the atoms have 10 protons and must also have 10 electrons. Isotopes Back to last Extension Questions 17. What characteristics of Model 1 are inconsistent with our understanding of what atoms look like? Note, limitations of models always exist, and we should be aware of them so we don’t try to use the model in situations where it does not really apply.
  • Investigative Science – ALIEN PERIODIC TABLE Tuesday September 17, 2013 Perry High School Mr

    Investigative Science – ALIEN PERIODIC TABLE Tuesday September 17, 2013 Perry High School Mr

    Investigative Science – ALIEN PERIODIC TABLE Tuesday September 17, 2013 Perry High School Mr. Pomerantz__________________________________________________________________________Page 1 of 2 Procedure: After reading the information below, correctly place the Alien elements in the periodic table based on the physical and chemical properties described. Imagine that scientists have made contact with life on a distant planet. The planet is composed of many of the same elements as are found on Earth. However, the in habitants of the planet have different names and symbols for the elements. The radio transmission gave data on the known chemical and physical properties of the first 30 elements that belong to Groups 1, 2, 13, 14, 15, 16, 17, and 18. SEE if you can place the elements into a blank periodic table based on the information. You may need your Periodic Table as a reference for this activity. Here is the information on the elements. 1. The noble gases are bombal (Bo), wobble, (Wo), jeptum (J) and logon (L). Among these gases, wobble has the greatest atomic mass and bombal has the least. Logon is lighter than jeptum. 2. The most reactive group of metals are xtalt (X), byyou (By), chow (Ch) and quackzil (Q). Of these metals, chow has the lowest atomic mass. Quackzil is in the same period as wobble. 3. The most reactive group of nonmetals are apstrom (A), volcania (V), and kratt (Kt). Volcania is in the same period as quackzil and wobble. 4. The metalloids are Ernst (E), highho (Hi), terriblum (T) and sississ (Ss). Sissis is the metalloid with the highest mass number.
  • Average Or Apparent Mass of an Element SCIENTIFIC Isotopes and Atomic Mass

    Average Or Apparent Mass of an Element SCIENTIFIC Isotopes and Atomic Mass

    Average or Apparent Mass of an Element SCIENTIFIC Isotopes and Atomic Mass Introduction At the beginning of the 19th century, John Dalton proposed his new atomic theory—all atoms of the same element are identical and equal in mass. It was a simple yet revolutionary theory. It was also not quite right. The discovery of radioactivity in the 20th century made it possible to study the actual structure and mass of atoms. Gradually, evidence was obtained that atoms of the same element could have different masses. These atoms were called isotopes. How are isotopes different from one another? What is the relationship between the atomic mass of an element and the mass of each isotope? Concepts • Isotope • Atomic and electron structure • Mass number • Atomic mass Materials Bags, zipper-lock, 15 Lima beans, 20 oz Balance, centigram (0.01-g precision) Navy beans, 4 oz Kidney beans, 12 oz Weighing dishes or small cups, 4 Labeling pen or marker Safety Precautions Although the materials used in this activity are considered nonhazardous, please observe all normal laboratory safety guidelines. The food- grade items that have been brought into the lab are considered laboratory chemicals and are for lab use only. Do not taste or ingest any materials in the chemistry laboratory. Wash hands thoroughly with soap and water before leaving the laboratory. Preparation “Bean bag” isotopes may be mixed in any proportion to prepare samples for analysis. The mixtures analyzed in the Sample Data section were prepared by mixing navy beans, kidney beans, and lima beans in the following proportion: 100 g navy beans, 280 g kidney beans, and 500 g lima beans (Note: 1 oz = 28.35 g).
  • Name Class Period Pre-AP Chemistry: Worksheet # 3.4 Date

    Name Class Period Pre-AP Chemistry: Worksheet # 3.4 Date

    Name Class Period Pre-AP Chemistry: Worksheet # 3.4 Date Directions: Write your answers to the following questions in the space provided. For problem solving, all of the work leading up to the final answer must be shown in order to receive credit. You will not receive credit for “Magic 1. Use the periodic table to separate these 12 elements into six pairs of elements having similar properties. Ca, K, Ga, P, Si, Rb, B, Sr, Sn, Cl, Bi, Br Ca & Sr K & Rb Ga & B P & Bi Si & Sn Cl & Br 2. Use the periodic table to identify by name and symbol the elements that have the following locations. Phosphorus a. Group 15, Period 3 Barium b. Groups 2, Period 6 3. Where are the metals usually found on the periodic table? Where are the nonmetals found? The metalloids? Metals are on the left side and in the center; nonmetals are in the upper-right corner; metalloids form a border between the metals and nonmetals. 4. What are the major differences in the physical properties of metals, nonmetals, and metalloids? Metals—have luster, are malleable and ductile, good conductors of heat and electricity Nonmetals—are dull, not good conductors of heat and electricity, are brittle Metalloids—tend to be brittle, are semiconductors of heat and electricitiy 5. List one distinctive characteristic for the halogens, one for the noble gases, and one for the alkali metals. The halogens are the most reactive nonmetals The noble gases are unreactive. The alkali metals are the most reactive metals. 6. Hydrogen is shown on some periodic tables in two places: both with the alkali metals and with the halogens.
  • Production of Aluminium and the Heavy Magnesium Isotopes in Asymptotic Giant Branch Stars

    Production of Aluminium and the Heavy Magnesium Isotopes in Asymptotic Giant Branch Stars

    CSIRO PUBLISHING www.publish.csiro.au/journals/pasa Publications of the Astronomical Society of Australia, 2003, 20, 279–293 Production of Aluminium and the Heavy Magnesium Isotopes in Asymptotic Giant Branch Stars A. I. Karakas and J. C. Lattanzio School of Mathematical Sciences, Monash University, Wellington Road, Clayton, Vic 3800, Australia [email protected] Received 2003 January 20, accepted 2003 May 30 Abstract: We investigate the production of aluminium and magnesium in asymptotic giant branch models covering a wide range in mass and composition. We evolve models from the pre-main sequence, through all intermediate stages, to near the end of the thermally-pulsing asymptotic giant branch phase. We then perform detailed nucleosynthesis calculations from which we determine the production of the magnesium and aluminium isotopes as a function of the stellar mass and composition. We present the stellar yields of sodium and the magnesium and aluminium isotopes. We discuss the abundance predictions from the stellar models in reference to abundance anomalies observed in globular cluster stars. Keywords: stars: AGB and post-AGB — stars: abundances — stars: interiors — stars: low mass — ISM: abundances 1 Introduction 1997; Siess, Livio, & Lattanzio 2002). There are currently In recent years our attempts to understand many aspects no quantitative studies of the production of the neutron- of nucleosynthesis and stellar evolution have come to rely rich Mg isotopes in low-metallicity WR stars. There are on our understanding of the production of the magne- quantitative studies of magnesium production in low- sium and aluminium isotopes. For example, abundance metallicityAGB stars (Forestini & Charbonnel 1997; Siess anomalies in globular cluster stars have been a problem et al.
  • Periodic Table 1 Periodic Table

    Periodic Table 1 Periodic Table

    Periodic table 1 Periodic table This article is about the table used in chemistry. For other uses, see Periodic table (disambiguation). The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers (numbers of protons in the nucleus), electron configurations , and recurring chemical properties. Elements are presented in order of increasing atomic number, which is typically listed with the chemical symbol in each box. The standard form of the table consists of a grid of elements laid out in 18 columns and 7 Standard 18-column form of the periodic table. For the color legend, see section Layout, rows, with a double row of elements under the larger table. below that. The table can also be deconstructed into four rectangular blocks: the s-block to the left, the p-block to the right, the d-block in the middle, and the f-block below that. The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table.
  • Pre and Post Tests Use the Periodic Table to Answer These Questions

    Pre and Post Tests Use the Periodic Table to Answer These Questions

    Pre and Post Tests Use the periodic table to answer these questions. MULTIPLE CHOICE 1. Neon is an example of a(n): A. Alkali Metal B. Noble Gas C. Halogen D. Rare Earth Metal 2. An element that has two valence or outer level electrons would be considered a(n): A. Nonmetal B. Noble Gas C. Halogen D. Metal 3. Sodium is in the same group or family as: A. Lithium B. Helium C. Calcium D. Thorium 4. Iodine is an example of a(n): A. Noble Gas B. Halogen C. Alkali Metal D. Rare Earth Metal 5. If an element is a gas at room temperature, then it must be a(n): A. Alkali Metal B. Nonmetal C. Halogen D. Alkaline Earth Metal 6. If an element has one to three valence or outer level electrons, then it is a(n): A. Nonmetal B. Halogen C. Noble Gas D. Metal 7. Which of the following elements belongs to the group that includes the most active metals? A. Aluminum B. Sodium C. Iron D. Mercury GRIDDED RESPONSE 8. How many valence or outer level electrons does an atom of the element argon have? _____________ SHORT RESPONSE 9. Barium and magnesium are both found in the same group in the periodic table. Name two properties that they would be expected to share. EXTENDED RESPONSE 10. Chlorine and bromine are both found in the same group in the periodic table. Name this group. Are these elements metals or nonmetals? How many valence electrons do they have? Name a property that these two elements would be expected to share.
  • Atomic Mass ƒ 4.6 – Electron Energy Levels Chapter 4 ƒ 4.7 – Electron Configurations ƒ 4.8 – Trends in Periodic Properties

    Atomic Mass ƒ 4.6 – Electron Energy Levels Chapter 4 ƒ 4.7 – Electron Configurations ƒ 4.8 – Trends in Periodic Properties

    Lecture Presentation 4.1 – Elements and Symbols 4.2 – The Periodic Table 4.3 – The Atom 4.4 – Atomic Number and Mass Number 4.5 – Isotopes and Atomic Mass 4.6 – Electron Energy Levels Chapter 4 4.7 – Electron Configurations 4.8 – Trends in Periodic Properties General, Organic, and Biological Chemistry: Structures of Life, 5/e © 2016 Pearson Education, Inc. Karen C. Timberlake Elements: are pure substances from which all other things are built. are listed on the periodic table. Goal : Given its name, write its correct symbol; from the symbol. Write the correct name. General, Organic, and Biological Chemistry: Structures of Life, 5/e © 2016 Pearson Education, Inc. Karen C. Timberlake Element names come from planets, mythological figures, Chemical symbols minerals, colors, geographic locations, and famous people. Carbon, C • represent the names of the elements. • consist of one to two letters and start with a capital letter. One-Letter Symbols Two-Letter Symbols C carbon Co cobalt N nitrogen Ca calcium F fluorine Al aluminum O oxygen Mg magnesium General, Organic, and Biological Chemistry: Structures of Life, 5/e © 2016 Pearson Education, Inc. General, Organic, and Biological Chemistry: Structures of Life, 5/e © 2016 Pearson Education, Inc. Karen C. Timberlake Karen C. Timberlake Write the correct chemical symbols for each of the following elements: A. iodine B. iron C. magnesium D. zinc E. nitrogen General, Organic, and Biological Chemistry: Structures of Life, 5/e © 2016 Pearson Education, Inc. Karen C. Timberlake Give the names of the elements with the following symbols: Mercury (Hg) Is a silvery, shiny element that is liquid at room A.
  • Melt Solidification and Late-Stage Evaporation in the Evolution of a FUN Inclusion from the Vigarano C3V Chondrite

    Melt Solidification and Late-Stage Evaporation in the Evolution of a FUN Inclusion from the Vigarano C3V Chondrite

    Gewfiimica ep Cosmodzimica Act@ Vol. 55, pp. 623437 Copyright Q 1991 Pergamon #es pk. Printed in U.S.A. Melt solidification and late-stage evaporation in the evolution of a FUN inclusion from the Vigarano C3V chondrite ANDREW M. DAVIS,’ GLENN J. MACPHERSON,~ ROBERT N. CLAYTON, 1*3*4TOSHIKO K. MAYEDA,’ PAUL J. SYLVESTER,~ LAWRENCE GROSSMAN,“~ RICHARD W. HINTON,*‘* and JOHN R. LAUGHLI~~ ‘Enrico Fermi Institute, University of Chicago, Chicago, IL 60637, USA *Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA 3Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA “Department of Chemistry, University of Chicago, Chicago, IL 60637, USA (Received March 26, 1990; accepted in revisedform November 29, 1990) Abstract-Vigarano 1623-S is a forsterite-bearing refractory inclusion in which oxygen, magnesium, and silicon show large degrees of mass-dependent isotopic fractionation. The core of 16234 consists of forsteritic olivine, fassaite, melilite (Ak&, and spinel, all of which show isotopic mass fractionation, averaging -30.6L/amu for magnesium and - lO.OL/amu for silicon; it is enclosed in a mantle consisting of aluminous melilite (Ak 16-6o),spinel, perovskite, and hibonite. Hibonite and spine1 in the mantle are enriched in heavy isotopes of magnesium by S- 1%/amu relative to the core. 1623-5 originally formed by solidification of a magnesium-rich melt. The endemic isotopic mass fractionation may have been caused by evaporation of that melt or may reflect an earlier evaporation event affecting the reservoir from which the interior of 1623-5 formed. Later fiash remelting of the outer part of the core, and vola- tilization of SiO2 and MgO from the melt so produced, caused formation of a mantle that is in isotopic and petrologic di~uili~~um with the core.
  • TABLE of CONTENTS Radiation, Radioactivity, and Risk Assessment

    TABLE of CONTENTS Radiation, Radioactivity, and Risk Assessment

    TABLE OF CONTENTS Radiation, Radioactivity, and Risk Assessment TABLE OF CONTENTS OVERVIEW — THE THREE “R’s”: RADIATION, RADIOACTIVITY, AND RISK ASSESSMENT (article) ...... 1 Table 1 — Radiation Doses ...................................................................................................................... 5 Table 2 — Comparing Radiation Risk to Other Risks ............................................................................... 5 Table 3 — Radioactivity of Some Natural and Man-Made Materials ........................................................ 6 Table 4 — Half-lives of Some Radioactive Isotopes and Their Uses ........................................................ 6 Table 5 — Units of Radiation and Radioactivity ........................................................................................ 7 INSTRUCTOR’S GUIDE ................................................................................................................................... 9 ACTIVITY 1 — LET’S INVESTIGATE ............................................................................................................... 15 ACTIVITY 2 — TIME LINE ................................................................................................................................ 19 ACTIVITY 3 — FINDING THE AGE OF A FOSSIL ........................................................................................... 25 ACTIVITY 4 — RADIOACTIVE GOLF BALL FINDER ..................................................................................... 29 ACTIVITY
  • Separation of Magnesium Isotopes by 1-Aza-12-Crown-4 Bonded Merrifield Peptide Resin

    Separation of Magnesium Isotopes by 1-Aza-12-Crown-4 Bonded Merrifield Peptide Resin

    Korean J. Chem. Eng., 18(5), 750-754 (2001) SHORT COMMUNICATION Separation of Magnesium Isotopes by 1-Aza-12-Crown-4 Bonded Merrifield Peptide Resin Dong Won Kim†, Byong Kwang Joen, Soo Han Kwon, Jae Sup Shin, Hai Il Ryu*, Jong Seung Kim** and Young Shin Joen*** Department of Chemistry, College of Natural Sciences, Chungbuk National University, Cheongju 361-763, Republic of Korea *Department of Chemistry Education, College of Education, Kongju National University, Kongju 314-701, Republic of Korea **Department of Chemistry, Konyang University, Nonsan 320-711, Republic of Korea ***Division of Chemical Analysis, Korea Atomic Energy Research Institute, Daejeon 305-606, Republic of Korea (Received 5 March 2001 • accepted 18 June 2001) Abstract− Magnesium isotope separation was investigated by chemical ion exchange with the 1-aza-12-crown-4 bonded Merrifield peptide resin using elution chromatography. The capacity of the novel azacrown ion exchanger was 1.0 meq/g dry resin. The heavier isotopes of magnesium were enriched in the resin phase, while the lighter isotopes were enriched in the solution phase. The single stage separation factor was determined according to the method of Glueckauf from the elution curve and isotopic assays. The separation factors of 24Mg2+-25Mg2+, 24Mg2+-26Mg2+, and 25Mg2+-26Mg2+ isotope pairs were 1.012, 1.024, and 1.011, respectively. Key words: Monoazacrown, Capacity, Distribution Coefficient, Magnesium Isotope, Separation, Isotope Effect, Chromatog- raphy INTRODUCTION bert et al. [1961] also reported that the isotope enrichment of magne- sium, calcium, strontium, and barium through the migration of ions It was reported that crown ethers might also be applicable to the in molten halides.