- In full:
- Gilbert Newton Lewis
- Born:
- Oct. 23, 1875, Weymouth, Mass., U.S.
- Died:
- March 23, 1946, Berkeley, Calif. (aged 70)
Gilbert N. Lewis
-
Who was Gilbert N. Lewis?
Gilbert N. Lewis (1875â1946) was an American physical chemist renowned for his extensive contributions to the field. His work included research in chemical thermodynamics, advancements to acid and base theories, and the study of deuterium.
Lewis is also known for the electron-pair model of the covalent bond. His work with valence electrons and their pivotal role in forming bonds between atoms led to his development of the Lewis structure, a method of representing valence electrons using dots around the element's symbol. In 1923, Lewis introduced a theory of acids and bases, defining an acid as any compound that can attach to an unshared pair of electrons in another molecule.
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What is Gilbert N. Lewis best known for in chemistry?
Gilbert N. Lewis, an American physical chemist, is best known for his contributions to chemical thermodynamics, most notably the electron-pair model of the covalent bond. In 1916, Lewis published his model equating the classical chemical bond with the sharing of a pair of electrons between the two bonded atoms. He introduced "electron dot diagrams," now known as Lewis structures, to symbolize the electronic structures of atoms and molecules.
Additionally, Lewis is known for his electronic theory of acids and bases. Introduced in 1923, the Lewis theory defines an acid as any compound that can attach itself to an unshared pair of electrons in another molecule, with the molecule providing the electron pair defined as a base.
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What are Lewis structures and why are they important?
Gilbert N. Lewis, an American chemist, introduced Lewis structures, also known as "electron dot diagrams," to represent the electronic structures of atoms and molecules. These diagrams use dots around the chemical symbol of an element to represent valence electrons and discuss bond formation as the transfer of dots from one symbol to another.
Lewis structures are important because they help establish the characteristics of chemical bonds. They show how atoms share electrons to achieve a stable electron configuration, typically an octet, which lowers the energy of the molecule. They are also useful for predicting when the octet rule is likely to be valid. Although Lewis's theory has limitations, such as not being quantitative, it remains a widely used tool for assessing the structures and properties of covalent species.
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How did Gilbert N. Lewis explain chemical bonding?
Gilbert N. Lewis, around 1916, explained chemical bonding by proposing that atoms bond through the sharing or transfer of electrons to achieve a stable valence shell, resembling that of a noble gas. He suggested that ionic bonds are formed via the complete transfer of electrons between atoms, whereas covalent bonds involve the sharing of electron pairs.
Lewis's octet rule states that atoms tend to gain, lose, or share electrons to attain an octet (eight electrons) in their valence shell. Lewis also introduced electron dot diagrams (now known as Lewis structures) to represent the electronic structures of molecules. These structures use dots around atomic symbols to depict valence electrons and lines to show shared electron pairs in covalent bonds.
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What is the Lewis theory of acids and bases?
In 1923, Gilbert N. Lewis introduced the Lewis theory, which generalized acids and bases. In this theory, an acid is a compound that can attach to an unshared electron pair in another molecule during a chemical reaction. The molecule with the available electron pair is a base. The reaction results in an addition compound where the chemical bond's electron pair comes from one reactant.
Lewis acids include metal ions, nonmetallic element oxides, substances donating hydrogen ions or protons, and compounds like aluminum chloride and boron trifluoride. Lewis bases include ammonia, alkali and alkaline earth metal oxides, and most negatively charged atoms and molecules. Lewis's work also covered chemical thermodynamics, covalent bonds, deuterium, phosphorescence, and the triplet state.
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How did Gilbert N. Lewis' ideas influence modern chemistry?
Gilbert N. Lewis, an American physical chemist, significantly shaped modern chemistry through his theories. His most notable contribution is the electron-pair model of the covalent bond, where he equated a chemical bond with the sharing of a pair of electrons between two bonded atoms.
Lewis introduced electron dot diagrams, now known as Lewis structures, to symbolize the electronic structures of atoms and molecules. These diagrams are a fundamental concept in introductory chemistry. Building on Lewis's work, the valence-shell electron-pair repulsion (VSEPR) theory helps predict molecular shapes by focusing on the role of electron pairs in minimizing repulsion. Additionally, Lewis's broader acid-base theory defines bases as electron-pair donors and acids as electron-pair acceptors, impacting how chemists understand and classify reactions.
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Gilbert N. Lewis (born Oct. 23, 1875, Weymouth, Mass., U.S.âdied March 23, 1946, Berkeley, Calif.) was an American physical chemist best known for his contributions to chemical thermodynamics, the electron-pair model of the covalent bond, the electronic theory of acids and bases, the separation and study of deuterium and its compounds, and his work on phosphorescence and the triplet state (in which the quantum number for total spin angular momentum is 1).
Education and academic career
Lewis spent his youth in Lincoln, Neb. Initially educated at home by his parents, at age 13 he entered the preparatory school of the University of Nebraska in Lincoln. He continued at the university through his sophomore year before transferring to Harvard University in 1893, from which he received a bachelorâs degree in chemistry in 1896. After a year of teaching at Phillips Academy in Andover, Mass., he returned to Harvard to complete a masterâs degree in 1898, followed by a doctorate the next year under the supervision of Theodore Richards for a dissertation on the electrochemistry of zinc and cadmium amalgams.
After graduation, Lewis remained at Harvard as an instructor for a year. He then pursued postgraduate work in the laboratories of Wilhelm Ostwald and Walther Nernst in Germany, before he returned for another three years as an instructor at Harvard and then a year in the Philippine Islands as superintendent of weights and measures. In 1905 Lewis joined the faculty of the Massachusetts Institute of Technology in Cambridge, and in 1912 he was appointed permanent dean of the college of chemistry and chair of the department of chemistry at the University of California at Berkeley, where he remained until his death at age 70 of an apparent heart attack while working in his laboratory. During his 34-year tenure at Berkeley, Lewis succeeded in molding its chemistry department into one of the best in the United States.
Though his appointment as chair at Berkeley relieved him of all classroom teaching duties, Lewis was well known for his insightful and often witty comments during student and staff research seminars. A brilliant conversationalist, with an almost unlimited supply of jokes and bon mots, Lewis was also addicted to the use of limericks and puns. He preferred to write his books and papers by dictating them to his assistants and collaborators, having fully composed his carefully crafted sentences in his head. When dictating, he would pace up and down the room while smoking an imported cigarâa habit picked up during his stay in the Philippines.
In 1912 Lewis married Mary Hinckley Sheldon, by whom he had three children, a daughter and two sons.
Chemical thermodynamics
Lewisâs major area of research was the field of chemical thermodynamics. In 1899 there was still a large gap between thermodynamic theory and practice. There was a complete theory of chemical equilibria, developed 20 years earlier by the American physicist Josiah Willard Gibbs, which showed that chemical equilibrium was determined by the free energies of the reacting substances. On the other hand, there was a vast amount of unorganized data on the enthalpies of reaction of chemical substances, collected earlier in the century by such chemists as Julius Thomsen of Denmark and Pierre-EugĂšne-Marcellin Berthelot of France. In addition, a series of empirical laws, dealing with the behaviour of ideal gases and dilute solutions, were developed that formed the substance of the newer physical chemistry championed by such chemists as Ostwald, Svante Arrhenius in Sweden, Jacobus van ât Hoff in the Netherlands, and Nernst. Lewis set himself the task of closing this gap between theory and practice. This required that he either directly measure the missing free-energy values for chemical substances or supplement the existing enthalpy data with entropy values, which would allow their calculation. Second, it was also necessary to find some way of extending the empirical laws to include the behaviour of real gases and concentrated solutions.
In pursuit of the first of these goals, Lewis initiated a vigorous experimental program designed to measure the missing free-energy and entropy values. In pursuit of the second goal, he successively introduced the concepts of fugacity (1901), activity coefficient (1907), and ionic strength (1921; a measure of the average electrostatic interactions among ions in a solution). These efforts culminated in 1923 in the publication of Thermodynamics and the Free Energy of Chemical Substances, written in collaboration with chemist Merle Randall.
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