A chemical element is a chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8, meaning each oxygen atom has 8 protons in its nucleus. Atoms of the same element can have different numbers of neutrons in their nuclei, known as isotopes of the element. Two or more atoms can combine to form molecules. Some elements are formed from molecules of identical atoms, e. g. atoms of hydrogen (H) form diatomic molecules (H2). Chemical compounds are substances made of atoms of different elements; they can have molecular or non-molecular structure. Mixtures are materials containing different chemical substances; that means (in case of molecular substances) that they contain different types of molecules. Atoms of one element can be transformed into atoms of a different element in nuclear reactions, which change an atom's atomic number.
The noble gases are the members of group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) and, in some cases, oganesson (Og). Under standard conditions, the first six of these elements are odorless, colorless, monatomic gases with very low chemical reactivity and cryogenic boiling points. The properties of the seventh, unstable, element, Og, are uncertain.
Oganesson is a synthetic chemical element; it has symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, near Moscow, Russia, by a joint team of Russian and American scientists. In December 2015, it was recognized as one of four new elements by the Joint Working Party of the international scientific bodies IUPAC and IUPAP. It was formally named on 28 November 2016. The name honors the nuclear physicist Yuri Oganessian, who played a leading role in the discovery of the heaviest elements in the periodic table. It is one of only two elements named after a person who was alive at the time of naming, the other being seaborgium, and the only element whose eponym is alive as of 2024.
Tennessine is a synthetic chemical element; it has symbol Ts and atomic number 117. It has the second-highest atomic number and joint-highest atomic mass of all known elements and is the penultimate element of the 7th period of the periodic table. It is named after the U.S. state of Tennessee, where key research institutions involved in its discovery are located.
An extended periodic table theorizes about chemical elements beyond those currently known and proven. The element with the highest atomic number known is oganesson (Z = 118), which completes the seventh period (row) in the periodic table. All elements in the eighth period and beyond thus remain purely hypothetical.
In the context of the periodic table a nonmetal is a chemical element that mostly lacks distinctive metallic properties. They range from colorless gases like hydrogen to shiny crystals like iodine. Physically, they are usually lighter than elements that form metals and are often poor conductors of heat and electricity. Chemically, nonmetals have relatively high electronegativity or usually attract electrons in a chemical bond with another element, and their oxides tend to be acidic.
A period 5 element is one of the chemical elements in the fifth 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 behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The fifth period contains 18 elements, beginning with rubidium and ending with xenon. As a rule, period 5 elements fill their 5s shells first, then their 4d, and 5p shells, in that order; however, there are exceptions, such as rhodium.
A cork borer, often used in a chemistry or biology laboratory, is a metal tool for cutting a hole in a cork or rubber stopper to insert glass tubing. Cork borers usually come in a set of nested sizes along with a solid pin for pushing the removed cork out of the borer. The individual borer is a hollow tube, tapered at the edge, generally with some kind of handle at the other end.
Sir Martyn Poliakoff is a British chemist known for his work on green chemistry and for being the main presenter on the popular YouTube channel Periodic Videos. The core subjects of his academic work are supercritical fluids, infrared spectroscopy and lasers. He is a research professor in chemistry at the University of Nottingham. As well as carrying out research at the University of Nottingham, he is a lecturer, teaching a number of modules including green chemistry.
Theodore W. "Theo" Gray is a co-founder of Wolfram Research, science author, and co-founder of app developer Touch Press.
Baron Jöns Jacob Berzelius (Swedish:[jœnsˈjɑ̌ːkɔbbæˈʂěːlɪɵs] was a Swedish chemist. In general, he is considered the last person to know the whole field of chemistry. Berzelius is considered, along with Robert Boyle, John Dalton, and Antoine Lavoisier, to be one of the founders of modern chemistry. Berzelius became a member of the Royal Swedish Academy of Sciences in 1808 and served from 1818 as its principal functionary. He is known in Sweden as the "Father of Swedish Chemistry". During his lifetime he did not customarily use his first given name, and was universally known simply as Jacob Berzelius.
Sigurd Hofmann was a German physicist known for his work on superheavy elements.
Yuri Tsolakovich Oganessian is a Soviet and Russian nuclear physicist who is best known as a researcher of superheavy chemical elements. He has led the discovery of multiple elements of the periodic table. He succeeded Georgy Flyorov as director of the Flyorov Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research in 1989 and is now its scientific director. The heaviest element known of the periodic table, oganesson, is named after him, only the second time that an element was named after a living person.
Ida Freund was the first woman to be a university chemistry lecturer in the United Kingdom. She is known for her influence on science teaching, particularly the teaching of women and girls. She wrote two key chemistry textbooks and invented the idea of baking periodic table cupcakes, as well as inventing a gas measuring tube, which was named after her.
Brady John Haran is an Australian-British independent filmmaker and video journalist who produces educational videos and documentary films for his YouTube channels, the most notable being Computerphile and Numberphile. Haran is also the co-host of the Hello Internet podcast along with fellow educational YouTuber CGP Grey. On 22 August 2017, Haran launched his second podcast, called The Unmade Podcast, and on 11 November 2018, he launched his third podcast, The Numberphile Podcast, based on his mathematics-centered channel of the same name.
Stephen T. Liddle FRSE FRSC is a British professor of inorganic chemistry at the University of Manchester. He is Head of Inorganic Chemistry and Co-Director of the Centre for Radiochemistry Research at the University of Manchester since 2015.
Derek Alexander Muller is a South African–Australian science communicator and media personality, best known for his YouTube channel Veritasium, which has over 16 million subscribers and 2.8 billion views as of October 2024.
Lieutenant Colonel Brian Duncan Shaw, was a British chemistry lecturer at the University of Nottingham, known for his demonstrations on explosives.
The Mystery of Matter: Search for the Elements is a 2014 American documentary miniseries, which premiered nationwide on August 19, 2015. The PBS documentary, in three-episodes of one hour each, was directed by Stephen Lyons and Muffie Meyer.
Alfred Gavin Maddock (1917–2009) was an English inorganic chemist, radiochemist and spectroscopist who worked on the Tube Alloys Project and the Manhattan Project during World War II. Those projects resulted in the development of the atomic bomb. He may be best known for, during World War II, spilling Canada's entire supply of plutonium which was 10 milligrams onto a wooden laboratory bench, and for recovered 9 and a half milligrams of plutonium. He recovered it by wet chemistry. He also had a distinguished, though less eventful, post-war academic career.
