Valence Electrons & Orbitals
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Unit 3 Notes: Periodic Table Notes John Newlands Proposed an Organization System Based on Increasing Atomic Mass in 1864
Unit 3 Notes: Periodic Table Notes John Newlands proposed an organization system based on increasing atomic mass in 1864. He noticed that both the chemical and physical properties repeated every 8 elements and called this the ____Law of Octaves ___________. In 1869 both Lothar Meyer and Dmitri Mendeleev showed a connection between atomic mass and an element’s properties. Mendeleev published first, and is given credit for this. He also noticed a periodic pattern when elements were ordered by increasing ___Atomic Mass _______________________________. By arranging elements in order of increasing atomic mass into columns, Mendeleev created the first Periodic Table. This table also predicted the existence and properties of undiscovered elements. After many new elements were discovered, it appeared that a number of elements were out of order based on their _____Properties_________. In 1913 Henry Mosley discovered that each element contains a unique number of ___Protons________________. By rearranging the elements based on _________Atomic Number___, the problems with the Periodic Table were corrected. This new arrangement creates a periodic repetition of both physical and chemical properties known as the ____Periodic Law___. Periods are the ____Rows_____ Groups/Families are the Columns Valence electrons across a period are There are equal numbers of valence in the same energy level electrons in a group. 1 When elements are arranged in order of increasing _Atomic Number_, there is a periodic repetition of their physical and chemical -
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. -
Chemistry Third Marking Period Review Sheet Spring, Mr
Chemistry Third Marking Period Review Sheet Spring, Mr. Wicks Chapters 7-8: Ionic and Covalent Bonding • I can explain the difference between core electrons and valence electrons. • I can write Lewis dot symbols for atoms of particular elements and show the gain or loss of electrons to form ionic compounds. • I can compare and contrast ionic and molecular compounds. See Table 1. • I can describe ionic and covalent bonding and explain the differences between them. • I can compare and contrast the properties of ionic and molecular compounds. • I can predict trends in bond length when comparing carbon-carbon single, double, and triple bonds. Table 1: Comparing Ionic and Molecular Compounds Ionic Compounds Molecular Compounds Bonding Type: Ionic Bonding Covalent Bonding In this type of bonding, electrons are _____: Transferred Shared Type(s) of Elements Involved: Metal + Nonmetal Elements Nonmetal Elements Comparison of Larger Smaller electronegativity differences: Comparison of Properties: a. Melting and boiling points: a. Higher a. Lower b. Hardness: b. Harder b. Softer c. Conduction of electricity: c. When molten or dissolved in c. Molecular compounds do water, ionic compounds tend to not conduct electricity. conduct electricity. • I can apply trends for electronegativity in the periodic table to solve homework problems. • I can use electronegativity differences to classify bonds as nonpolar covalent, polar covalent, and ionic. See Table 2. Table 2: Classifying Bonds Using Electronegativity Differences Electronegativity Difference Bond Type 0 - 0.2 Nonpolar covalent bond 0.3 - 1.9 Polar covalent bond ≥ 2.0 Ionic bond Chemistry Third Marking Period Review Sheet, Page 2 • I can apply the octet rule to write Lewis structures for molecular compounds and polyatomic ions. -
Actinide Ground-State Properties-Theoretical Predictions
Actinide Ground-State Properties Theoretical predictions John M. Wills and Olle Eriksson electron-electron correlations—the electronic energy of the ground state of or nearly fifty years, the actinides interactions among the 5f electrons and solids, molecules, and atoms as a func- defied the efforts of solid-state between them and other electrons—are tional of electron density. The DFT Ftheorists to understand their expected to affect the bonding. prescription has had such a profound properties. These metals are among Low-symmetry crystal structures, impact on basic research in both the most complex of the long-lived relativistic effects, and electron- chemistry and solid-state physics that elements, and in the solid state, they electron correlations are very difficult Walter Kohn, its main inventor, was display some of the most unusual to treat in traditional electronic- one of the recipients of the 1998 behaviors of any series in the periodic structure calculations of metals and, Nobel Prize in Chemistry. table. Very low melting temperatures, until the last decade, were outside the In general, it is not possible to apply large anisotropic thermal-expansion realm of computational ability. And DFT without some approximation. coefficients, very low symmetry crystal yet, it is essential to treat these effects But many man-years of intense research structures, many solid-to-solid phase properly in order to understand the have yielded reliable approximate transitions—the list is daunting. Where physics of the actinides. Electron- expressions for the total energy in does one begin to put together an electron correlations are important in which all terms, except for a single- understanding of these elements? determining the degree to which 5f particle kinetic-energy term, can be In the last 10 years, together with electrons are localized at lattice sites. -
Chapter 7 Electron Configuration and the Periodic Table
Chapter 7 Electron Configuration and the Periodic Table Copyright McGraw-Hill 2009 1 7.1 Development of the Periodic Table • 1864 - John Newlands - Law of Octaves- every 8th element had similar properties when arranged by atomic masses (not true past Ca) • 1869 - Dmitri Mendeleev & Lothar Meyer - independently proposed idea of periodicity (recurrence of properties) Copyright McGraw-Hill 2009 2 • Mendeleev – Grouped elements (66) according to properties – Predicted properties for elements not yet discovered – Though a good model, Mendeleev could not explain inconsistencies, for instance, all elements were not in order according to atomic mass Copyright McGraw-Hill 2009 3 • 1913 - Henry Moseley explained the discrepancy – Discovered correlation between number of protons (atomic number) and frequency of X rays generated – Today, elements are arranged in order of increasing atomic number Copyright McGraw-Hill 2009 4 Periodic Table by Dates of Discovery Copyright McGraw-Hill 2009 5 Essential Elements in the Human Body Copyright McGraw-Hill 2009 6 The Modern Periodic Table Copyright McGraw-Hill 2009 7 7.2 The Modern Periodic Table • Classification of Elements – Main group elements - “representative elements” Group 1A- 7A – Noble gases - Group 8A all have ns2np6 configuration(exception-He) – Transition elements - 1B, 3B - 8B “d- block” – Lanthanides/actinides - “f-block” Copyright McGraw-Hill 2009 8 Periodic Table Colored Coded By Main Classifications Copyright McGraw-Hill 2009 9 Copyright McGraw-Hill 2009 10 • Predicting properties – Valence -
Of the Periodic Table
of the Periodic Table teacher notes Give your students a visual introduction to the families of the periodic table! This product includes eight mini- posters, one for each of the element families on the main group of the periodic table: Alkali Metals, Alkaline Earth Metals, Boron/Aluminum Group (Icosagens), Carbon Group (Crystallogens), Nitrogen Group (Pnictogens), Oxygen Group (Chalcogens), Halogens, and Noble Gases. The mini-posters give overview information about the family as well as a visual of where on the periodic table the family is located and a diagram of an atom of that family highlighting the number of valence electrons. Also included is the student packet, which is broken into the eight families and asks for specific information that students will find on the mini-posters. The students are also directed to color each family with a specific color on the blank graphic organizer at the end of their packet and they go to the fantastic interactive table at www.periodictable.com to learn even more about the elements in each family. Furthermore, there is a section for students to conduct their own research on the element of hydrogen, which does not belong to a family. When I use this activity, I print two of each mini-poster in color (pages 8 through 15 of this file), laminate them, and lay them on a big table. I have students work in partners to read about each family, one at a time, and complete that section of the student packet (pages 16 through 21 of this file). When they finish, they bring the mini-poster back to the table for another group to use. -
Periodic Trends Lab CHM120 1The Periodic Table Is One of the Useful
Periodic Trends Lab CHM120 1The Periodic Table is one of the useful tools in chemistry. The table was developed around 1869 by Dimitri Mendeleev in Russia and Lothar Meyer in Germany. Both used the chemical and physical properties of the elements and their tables were very similar. In vertical groups of elements known as families we find elements that have the same number of valence electrons such as the Alkali Metals, the Alkaline Earth Metals, the Noble Gases, and the Halogens. 2Metals conduct electricity extremely well. Many solids, however, conduct electricity somewhat, but nowhere near as well as metals, which is why such materials are called semiconductors. Two examples of semiconductors are silicon and germanium, which lie immediately below carbon in the periodic table. Like carbon, each of these elements has four valence electrons, just the right number to satisfy the octet rule by forming single covalent bonds with four neighbors. Hence, silicon and germanium, as well as the gray form of tin, crystallize with the same infinite network of covalent bonds as diamond. 3The band gap is an intrinsic property of all solids. The following image should serve as good springboard into the discussion of band gaps. This is an atomic view of the bonding inside a solid (in this image, a metal). As we can see, each of the atoms has its own given number of energy levels, or the rings around the nuclei of each of the atoms. These energy levels are positions that electrons can occupy in an atom. In any solid, there are a vast number of atoms, and hence, a vast number of energy levels. -
Periodic Table of the Elements Notes
Periodic Table of the Elements Notes Arrangement of the known elements based on atomic number and chemical and physical properties. Divided into three basic categories: Metals (left side of the table) Nonmetals (right side of the table) Metalloids (touching the zig zag line) Basic Organization by: Atomic structure Atomic number Chemical and Physical Properties Uses of the Periodic Table Useful in predicting: chemical behavior of the elements trends properties of the elements Atomic Structure Review: Atoms are made of protons, electrons, and neutrons. Elements are atoms of only one type. Elements are identified by the atomic number (# of protons in nucleus). Energy Levels Review: Electrons are arranged in a region around the nucleus called an electron cloud. Energy levels are located within the cloud. At least 1 energy level and as many as 7 energy levels exist in atoms Energy Levels & Valence Electrons Energy levels hold a specific amount of electrons: 1st level = up to 2 2nd level = up to 8 3rd level = up to 8 (first 18 elements only) The electrons in the outermost level are called valence electrons. Determine reactivity - how elements will react with others to form compounds Outermost level does not usually fill completely with electrons Using the Table to Identify Valence Electrons Elements are grouped into vertical columns because they have similar properties. These are called groups or families. Groups are numbered 1-18. Group numbers can help you determine the number of valence electrons: Group 1 has 1 valence electron. Group 2 has 2 valence electrons. Groups 3–12 are transition metals and have 1 or 2 valence electrons. -
Electronegativity Seen As the Ground-State
Article Cite This: J. Am. Chem. Soc. 2019, 141, 342−351 pubs.acs.org/JACS Electronegativity Seen as the Ground-State Average Valence Electron Binding Energy † ‡ § Martin Rahm,*, Tao Zeng, and Roald Hoffmann † Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden ‡ Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada § Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States *S Supporting Information ABSTRACT: We introduce a new electronegativity scale for atoms, based consistently on ground-state energies of valence electrons. The scale is closely related to (yet different from) L. C. Allen’s, which is based on configuration energies. Using a combination of literature experimental values for ground-state energies and ab initio- calculated energies where experimental data are missing, we are able to provide electronegativities for elements 1−96. The values are slightly smaller than Allen’s original scale, but correlate well with Allen’s and others. Outliers in agreement with other scales are oxygen and fluorine, now somewhat less electronegative, but in better agreement with their chemistry with the noble gas elements. Group 11 and 12 electronegativities emerge as high, although Au less so than in other scales. Our scale also gives relatively high electronegativities for Mn, Co, Ni, Zn, Tc, Cd, Hg (affected by choice of valence state), and Gd. The new electronegativities provide hints for new alloy/compound design, -
Organometallic Pnictogen Chemistry
Institut für Anorganische Chemie 2014 Fakultät für Chemie und Pharmazie | Sabine Reisinger aus Regensburg, geb. Scheuermayer am 15.07.1983 Studium: Chemie, Universität Regensburg Abschluss: Diplom Promotion: Prof. Dr. Manfred Scheer, Institut für Anorganische Chemie Sabine Reisinger Die vorliegende Arbeit enthält drei Kapitel zu unterschiedlichen Aspekten der metallorganischen Phosphor- und Arsen-Chemie. Zunächst werden Beiträge zur supramolekularen Chemie mit 5 Pn-Ligandkomplexen basierend auf [Cp*Fe(η -P5)] und 5 i [Cp*Fe(η - Pr3C3P2)] gezeigt, gefolgt von der Eisen-vermittelten Organometallic Pnictogen Aktivierung von P4, die zu einer selektiven C–P-Bindungsknüpfung führt, während das dritte Kapitel die Verwendung von Phosphor Chemistry – Three Aspects und Arsen als Donoratome in mehrkernigen Komplexen mit paramagnetischen Metallionen behandelt. Sabine Reisinger 2014 Alumniverein Chemie der Universität Regensburg E.V. [email protected] http://www.alumnichemie-uniregensburg.de Aspects Three – Chemistry Pnictogen Organometallic Fakultät für Chemie und Pharmazie ISBN 978-3-86845-118-4 Universität Regensburg Universitätsstraße 31 93053 Regensburg www.uni-regensburg.de 9 783868 451184 4 Sabine Reisinger Organometallic Pnictogen Chemistry – Three Aspects Organometallic Pnictogen Chemistry – Three Aspects Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften (Dr. rer. nat.) der Fakultät für Chemie und Pharmazie der Universität Regensburg vorgelegt von Sabine Reisinger, geb. Scheuermayer Regensburg 2014 Die Arbeit wurde von Prof. Dr. Manfred Scheer angeleitet. Das Promotionsgesuch wurde am 20.06.2014 eingereicht. Das Kolloquium fand am 11.07.2014 statt. Prüfungsausschuss: Vorsitzender: Prof. Dr. Helmut Motschmann 1. Gutachter: Prof. Dr. Manfred Scheer 2. Gutachter: Prof. Dr. Henri Brunner weiterer Prüfer: Prof. Dr. Bernhard Dick Dissertationsreihe der Fakultät für Chemie und Pharmazie der Universität Regensburg, Band 4 Herausgegeben vom Alumniverein Chemie der Universität Regensburg e.V. -
Periodic Table Key Concepts
Periodic Table Key Concepts Periodic Table Basics The periodic table is a table of all the elements which make up matter Elements initially grouped in a table by Dmitri Mendeleev Symbols – each element has a symbol which is either a Capital Letter or a Capital Letter followed by a lower case letter Atomic Number – the number above an element’s symbol which shows the number of protons Atomic Mass – the number found below an elements symbol which shows the mass of the element. Mass = the number of protons + the number of neutrons Metals – the elements which have the properties of malleability, luster, and conductivity o These elements are good conductors of electricity & heat. o Found to the left of the zig-zag line on the periodic table Nonmetals – do not have the properties of metals. Found to the right of the zig-zag line Metalloids – elements found along the zig-zag line of the periodic table and have some properties of metals and nonmetals (B, Si, Ge, As, Sb, Te, and Po) Groups The columns going up and down (There are 18 groups) Group 1: Hydrogen, Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium Elements arranged so that elements with similar properties would be in the same group. o Group 1 Alkali Metals - highly reactive metals o Group 2 Alkali Earth Metals – reactive metals o Group 3-12 Transition Metals o Group 17 Halogens – highly reactive non-metals o Group 18 Noble Gases - do not react or combine with any other elements. Elements are grouped according to their properties or reactivity Reactivity is determined by the number of electrons in an element’s outer energy level These electrons are called valence electrons Periods The rows that run from left to right on the periodic table (There are 7 periods) Period 1 contains 2 elements, Hydrogen and Helium. -
Octet Rule & Ions
Chemistry 51 Chapter 5 OCTET RULE & IONS Most elements, except noble gases, combine to form compounds. Compounds are the result of the formation of chemical bonds between two or more different elements. In the formation of a chemical bond, atoms lose, gain or share valence electrons to complete their outer shell and attain a noble gas configuration. This tendency of atoms to have eight electrons in their outer shell is known as the octet rule. Formation of Ions: An ion (charged particle) can be produced when an atom gains or loses one or more electrons. A cation (+ ion) is formed when a neutral atom loses an electron. An anion (- ion) is formed when a neutral atom gains an electron. 1 Chemistry 51 Chapter 5 IONIC CHARGES The ionic charge of an ion is dependent on the number of electrons lost or gained to attain a noble gas configuration. For most main group elements, the ionic charges can be determined from their group number, as shown below: All other ionic charges need to be memorized and known in order to write correct formulas for the compounds containing them. 2 Chemistry 51 Chapter 5 COMPOUNDS Compounds are pure substances that contain 2 or more elements combined in a definite proportion by mass. Compounds can be classified as one of two types: Ionic and molecular (covalent) Ionic compounds are formed by combination of a metal and a non-metal. The smallest particles of ionic compounds are ions. Molecular compounds are formed by combination of 2 or more non-metals. The smallest particles of molecular compounds are molecules.