Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds.
Henry Gwyn Jeffreys Moseley was an English physicist, whose contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number. This stemmed from his development of Moseley's law in X-ray spectra.
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ("groups"). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order of their atomic numbers an approximate recurrence of their properties is evident. The table is divided into four roughly rectangular areas called blocks. Elements in the same group tend to show similar chemical characteristics.
Dmitri Ivanovich Mendeleev was a Russian chemist and inventor. He is best known for formulating the Periodic Law and creating a version of the periodic table of elements. He used the Periodic Law not only to correct the then-accepted properties of some known elements, such as the valence and atomic weight of uranium, but also to predict the properties of three elements that were yet to be discovered.
In chemistry, a group is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the 14 f-block columns, between groups 2 and 3, are not numbered. The elements in a group have similar physical or chemical characteristics of the outermost electron shells of their atoms, because most chemical properties are dominated by the orbital location of the outermost electron.
Antoine François Fourcroy was a French chemist and a contemporary of Antoine Lavoisier. Fourcroy collaborated with Lavoisier, Guyton de Morveau, and Claude Berthollet on the Méthode de nomenclature chimique, a work that helped standardize chemical nomenclature.
A period 1 element is one of the chemical elements in the first row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate periodic (recurring) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that analog elements fall into the same vertical columns. The first period contains fewer elements than any other row in the table, with only two: hydrogen and helium. This situation can be explained by modern theories of atomic structure. In a quantum mechanical description of atomic structure, this period corresponds to the filling of the 1s orbital. Period 1 elements obey the duet rule in that they need two electrons to complete their valence shell.
A period 7 element is one of the chemical elements in the seventh row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases: a new row is begun when chemical behavior begins to repeat, meaning that elements with similar behavior fall into the same vertical columns. The seventh period contains 32 elements, tied for the most with period 6, beginning with francium and ending with oganesson, the heaviest element currently discovered. As a rule, period 7 elements fill their 7s shells first, then their 5f, 6d, and 7p shells in that order, but there are exceptions, such as uranium.
John Alexander Reina Newlands was a British chemist who worked concerning the periodicity of elements.
The periodic table is an arrangement of the chemical elements, structured by their atomic number, electron configuration and recurring chemical properties. In the basic form, elements are presented in order of increasing atomic number, in the reading sequence. Then, rows and columns are created by starting new rows and inserting blank cells, so that rows (periods) and columns (groups) show elements with recurring properties. For example, all elements in group (column) 18 are noble gases that are largely—though not completely—unreactive.
Julius Lothar Meyer was a German chemist. He was one of the pioneers in developing the earliest versions of the periodic table of the chemical elements. The Russian chemist Dmitri Mendeleev and he had both worked with Robert Bunsen. Meyer never used his first given name and was known throughout his life simply as Lothar Meyer.
The philosophy of chemistry considers the methodology and underlying assumptions of the science of chemistry. It is explored by philosophers, chemists, and philosopher-chemist teams. For much of its history, philosophy of science has been dominated by the philosophy of physics, but the philosophical questions that arise from chemistry have received increasing attention since the latter part of the 20th century.
The history of chemistry represents a time span from ancient history to the present. By 1000 BC, civilizations used technologies that would eventually form the basis of the various branches of chemistry. Examples include the discovery of fire, extracting metals from ores, making pottery and glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering fat into soap, making glass, and making alloys like bronze.
The World of Chemistry is a television series on introductory chemistry hosted by Nobel prize-winning chemist Roald Hoffmann. The series consists of 26 half-hour video programs, along with coordinated books, which explore various topics in chemistry through experiments conducted by Stevens Point emeritus professor Don Showalter the "series demonstrator" and interviews with working chemists, it also includes physics and earth science related components. The series was produced by the University of Maryland, College Park and the Educational Film Center and was funded by the Annenberg/CPB Project, it was filmed in 1988 and first aired on PBS in 1990. This series supports science standards recognized nationally by the United States and is still widely used in high school and college chemistry courses. The entire series was previously available on learner.org for free in an online video streaming format, but streaming for this series was discontinued on June 25, 2019.
Since Dimitri Mendeleev formulated the periodic law in 1871, and published an associated periodic table of chemical elements, authors have experimented with varying types of periodic tables including for teaching, aesthetic or philosophical purposes.
Mary Elvira Weeks was an American chemist and historian of science. Weeks was the first woman to receive a Ph.D. in chemistry at the University of Kansas and the first woman to be a faculty member there.
Eric R. Scerri is a chemist, writer and philosopher of science of Maltese origin. He is a lecturer at the University of California, Los Angeles; and the founder and editor-in-chief of Foundations of Chemistry, an international peer reviewed journal covering the history and philosophy of chemistry, and chemical education.
The Bomb is a 2015 American documentary film about the history of nuclear weapons, from theoretical scientific considerations at the very beginning, to their first use on August 6, 1945, to their global political implications in the present day. The film was written and directed by Rushmore DeNooyer for PBS. The project took a year and a half to complete, since much of the film footage and images were only recently declassified by the United States Department of Defense.
Compound Interest is a website launched in 2013 by Andy Brunning with infographics on everyday chemistry. The infographics describe, for example, how chemicals found in food and nature give them smell, taste, and color. The website has a monthly collaboration with the American Chemical Society. Content of the website is used as information source by various newspapers and media, including the Washington Post, Time, The Conversation, and Forbes.
William Barry Jensen is an American chemist and chemical historian.
