chain reaction, in chemistry and physics, process yielding products that initiate further processes of the same kind, a self-sustaining sequence. Examples from chemistry are burning a fuel gas, the development of rancidity in fats, “knock” in internal-combustion engines, and the polymerization of

chain reaction: Nuclear chain reactions are series of nuclear fissions (splitting of atomic nuclei), each initiated by a neutron produced in a preceding fission. For example, 212 neutrons on the average are released by the fission of each uranium-235 nucleus that absorbs a low-energy neutron. Provided that…

chain rule, in calculus, basic method for differentiating a composite function. If f(x) and g(x) are two functions, the composite function f(g(x)) is calculated for a value of x by first evaluating g(x) and then evaluating the function f at this value of g(x), thus “chaining” the results together;

saw: The portable chain saw has practically replaced the woodman’s axe and the two-man hand saw for felling trees. It consists of a thin metal frame supporting a steel roller chain carrying saw teeth attached at intervals along its length; the teeth are slightly wider than the chain…

military technology: Special-purpose shot: Bar shot and chain shot consisted of two heavy projectiles joined by a bar or a chain. Whirling in their trajectories, they were especially effective at sea in cutting the spars and rigging of sailing vessels.

inosilicate, any of a class of inorganic compounds that have structures characterized by silicate tetrahedrons (each of which consists of a central silicon atom surrounded by four oxygen atoms at the corners of a tetrahedron) arranged in chains. Two of the oxygen atoms of each tetrahedron are

chain store, any of two or more retail stores having the same ownership and selling the same lines of goods. Chain stores account for an important segment of retailing operations in the Americas, western Europe, and Japan. Together with the department store and the mail-order company, chain stores

chemistry of industrial polymers: Free-radical initiation: …as backbiting or, more technically, chain transfer. The result is a polymer chain with the branched structure of low-density polyethylene (LDPE), also shown in Figure 1B. Chain-transfer reactions may also occur intermolecularly.

Sir Ernst Boris Chain was a German-born British biochemist who, with pathologist Howard Walter Florey, isolated and purified penicillin (which had been discovered in 1928 by Sir Alexander Fleming) and performed the first clinical trials of the antibiotic. For their pioneering work on penicillin,

generalized exchange: …one another is also called network-generalized or chain-generalized exchange. In addition, this form of generalized exchange is sometimes referred to as a gift economy. However, generalized exchange systems do not have explicit reciprocity between participants (as some gift economies do). The indirect nature of generalized exchange distinguishes it from similar…

surface coating: Step-growth and chain-growth polymers: Step-growth polymers include polyesters, epoxies, polyurethanes, polyamides, melamine, and phenolic resins. They are formed most often by reactions between two dissimilar monomers—acids and

polymerization: In addition polymerization, monomers react to form a polymer without the formation of by-products. Addition polymerizations usually are carried out in the presence of catalysts, which in certain cases exert control over structural details that have important effects on the properties of the polymer.

chemical kinetics: Composite reaction mechanisms: …regenerated are known as the chain-propagating steps. The average number of times the pair of steps is repeated is known as the chain length.

Annamese Cordillera, principal mountain range of Southeast Asia and the watershed between the Mekong River and the South China Sea. It extends parallel to the coast in a gentle curve generally northwest-southeast, forming the boundary between Laos and Vietnam. A fairly continuous range for about

Dângrêk Mountains, forested range of hills averaging 1,500–2,000 feet (450–600 m) and dividing Thailand from Cambodia. This east–west-trending range extends from the Mekong River westward for approximately 200 miles (320 km), merging with the highland area near San Kamphaeng, Thailand. Essentially

Krâvanh Mountains, range of high hills in southwestern Cambodia that is situated on a southeast-northwest axis and continues westward into the highland area around Chanthaburi, Thailand. The Krâvanh Mountains extend (some discontinuously) for about 100 miles (160 km) southeast and east to the

France: The Massif Central: …the Limagne, is the extraordinary Chaîne des Puys, whose numerous cinder cones were formed only about 10,000 years ago and still retain the newness of their craters, lava flows, and other volcanic features. Numerous mineral springs, such as those at Vichy in the central Auvergne region, are a relic of…

Dominican Republic: Relief, drainage, and soils: …to the south is the Sierra de Neiba, which corresponds to the Matheux and Trou d’Eau mountains of Haiti; its high peaks reach approximately 7,200 feet (2,200 metres). Water flowing off the Neiba range drains partly to the Caribbean, via the Yaque del Sur system, and partly inland, to saline…

La Rochelle: Opposite it stands the Tower de la Chaîne, so named because at night a big chain was strung between it and Saint-Nicolas Tower to close the port. In the 15th century a third tower, the Tower de la Lanterne, a round base surmounted by an octagonal spire, was built…

catenary, in mathematics, a curve that describes the shape of a flexible hanging chain or cable—the name derives from the Latin catenaria (“chain”). Any freely hanging cable or string assumes this shape, also called a chainette, if the body is of uniform mass per unit of length and is acted upon

Saint Kenneth ; feast day October 11) was an Irish abbot, monastic founder, and missionary who contributed to the conversion of the Picts. He is one of the most popular Celtic saints in Scotland (where he is called Kenneth) and in Ireland (where he is called Canice) and patron saint of the diocese

Jean-Paul Marat: Early scientific work: His early political works included The Chains of Slavery (1774), an attack on despotism addressed to British voters, in which he first expounded the notion of an “aristocratic,” or “court,” plot; it would become the principal theme of a number of his articles.

chair, seat with a back, intended for one person. It is one of the most ancient forms of furniture, dating from the 3rd dynasty of ancient Egypt (c. 2650–c. 2575 bce). It was common for early Egyptian chairs to have legs shaped like those of animals. The seats were corded or dished (hollowed) in

chairperson, senior officer of a committee, board, or organization responsible for presiding over its annual general meeting. The term also refers to the person in charge of meetings in general, as opposed to an attendee or a participant. There are several common variants of the term, each of which

hydrocarbon: Cycloalkanes: …conformations of cyclohexane, designated as chair, boat, and skew (or twist), are essentially free of angle strain. Of these three the chair is the most stable, mainly because it has a staggered arrangement of all its bonds. The boat and skew conformations lack perfect staggering of bonds and are destabilized…

Paul Adam: …of his first naturalist novel, Chair molle (1885), led to his being prosecuted; his second, Le Thé chez Miranda (1886), written with Jean Moréas, is an early example of Symbolism. Adam also founded two literary reviews in 1886: Led Carcan, with Jean Ajalbert, and the short-lived Le Symboliste, with Moréas…

Sandra Oh: …time she also starred in The Chair (2021), which aired on Netflix. The six-episode comedy drama centres on a university’s English department that is struggling amid various crises.

Indonesia: Literature: …of the early 1940s, with Chairil Anwar as the leading figure. Although he died young, Chairil transformed the Indonesian literary scene through the intense imagery of his poetry and through his rebellious stance toward religion and social convention.

China: Role of the CCP: …1982 the CCP had a chairmanship that was unique among ruling communist parties. Mao Zedong held this office until his death in 1976, and Hua Guofeng was chairman until his removal from office in 1981. Hu Yaobang then served as party chairman until the post was abolished in 1982. The…

chairperson, senior officer of a committee, board, or organization responsible for presiding over its annual general meeting. The term also refers to the person in charge of meetings in general, as opposed to an attendee or a participant. There are several common variants of the term, each of which

Whitey Ford was an American professional baseball player who was one of the best pitchers on a dominant New York Yankees team that won six World Series championships during his tenure (1950–67). After an outstanding rookie season in 1950, when he won 9 games and lost only 1, while posting an earned

In the United States, the chairman of the Joint Chiefs of Staff is the principal military adviser to the president, the secretary of defense, and the National Security Council. The position was created by the 1949 amendments to the National Security Act of 1947. The president appoints the chairman,

chairperson, senior officer of a committee, board, or organization responsible for presiding over its annual general meeting. The term also refers to the person in charge of meetings in general, as opposed to an attendee or a participant. There are several common variants of the term, each of which

comedy: The absurd: …stage full of chairs in The Chairs or the growing corpse in Amédée); the comic quality in these plays is one that Bergson would have appreciated. But the comic in Ionesco’s most serious work, as in so much of mid-20th-century theatre, has ominous implications that give to it a distinctly…

chairperson, senior officer of a committee, board, or organization responsible for presiding over its annual general meeting. The term also refers to the person in charge of meetings in general, as opposed to an attendee or a participant. There are several common variants of the term, each of which

chaise, (French: “chair”), originally a closed, two-wheeled, one-passenger, one-horse carriage of French origin, adapted from the sedan chair. The carrying poles, or shafts, were attached to the horse’s harness in front and fixed to the axle in back. The body of the carriage was set in front of the

chaise longue, a long seat for reclining on. Developed in the 18th century, it closely resembled the daybed of the late 17th century and the bergère armchair, but with an extension of the seat beyond the front of the arms. Some chaise longues, said to be brisée, or broken, were divided into two or

comedy: The absurd: …stage full of chairs in The Chairs or the growing corpse in Amédée); the comic quality in these plays is one that Bergson would have appreciated. But the comic in Ionesco’s most serious work, as in so much of mid-20th-century theatre, has ominous implications that give to it a distinctly…

Chaitanya was a Hindu mystic whose mode of worshipping the god Krishna with ecstatic song and dance had a profound effect on Vaishnavism in Bengal. The son of a Brahman, he grew up in an atmosphere of piety and affection. He received a thorough education in the Sanskrit scriptures and, after the

Chaitanya movement, intensely emotional movement of Hinduism that has flourished from the 16th century, mainly in Bengal and eastern Odisha (Orissa) state, India. It takes its name from the medieval saint Chaitanya (1485–1533), whose fervent devotion to the god Krishna inspired the movement. For

Chaitanya movement, intensely emotional movement of Hinduism that has flourished from the 16th century, mainly in Bengal and eastern Odisha (Orissa) state, India. It takes its name from the medieval saint Chaitanya (1485–1533), whose fervent devotion to the god Krishna inspired the movement. For

information theory: Algorithmic information theory: …the 1960s the American mathematician Gregory Chaitin, the Russian mathematician Andrey Kolmogorov, and the American engineer Raymond Solomonoff began to formulate and publish an objective measure of the intrinsic complexity of a message. Chaitin, a research scientist at IBM, developed the largest body of work and polished the ideas into…

South Asian arts: Folk dance: …of vignettes at the annual Chaitra Parva festival in April. Chhau masks have predominantly human features slightly modified to suggest what they are portraying. With serene expressions painted in simple, flat colours, they differ radically from the elaborate facial makeup of kathakali or the exaggerated ghoulishness of the Kandyan masks.…

Karli: …noted for the nearby rock-cut caitya, or Buddhist sanctuary. The caitya is of the normal apsidal plan, 124 feet (38 metres) long, 46.5 feet (14 metres) wide, and about 45 feet (13.5 metres) high to the crown of its teak-ribbed vault. It was dedicated in the first quarter of the…

screamer: The crested screamer, or chaja (a name that comes from its cry; Chauna torquata), of open country in east-central South America, and the black-necked screamer (C. chavaria), of Colombia and Venezuela, have hind crests of feathers.

Chajang Yulsa was a Buddhist monk who attempted to make Buddhism the Korean state religion. Chajang entered the Buddhist priesthood in Korea and then in 636 went to T’ang-dynasty China, where he spent seven years studying and practicing Buddhist teachings. On returning home, he brought with him

Chajang Yulsa was a Buddhist monk who attempted to make Buddhism the Korean state religion. Chajang entered the Buddhist priesthood in Korea and then in 636 went to T’ang-dynasty China, where he spent seven years studying and practicing Buddhist teachings. On returning home, he brought with him

Shaka was a Zulu chief (1816–28), founder of Southern Africa’s Zulu Empire. He is credited with creating a fighting force that devastated the entire region. His life is the subject of numerous colourful and exaggerated stories, many of which are debated by historians. Shaka was the son of

African literature: Southern Sotho: Chaka is a novel about Shaka; it is an effective blending of Sotho oral tradition and contemporary historical reality and, from the point of view of storytelling, a yoking of oral and literary forms. Mofolo depends on the oral tradition—more specifically, the traditional heroic cycle—for…

African literature: Shona: …during the 20th century was Patrick Chakaipa. His Karikoga gumiremiseve (1958; “Karikoga and His Ten Arrows”) is a blend of fantasy (it is based on a tale from the Shona oral tradition) and history, a love story focusing on conflicts between Shona and Ndebele peoples. Pfumo reropa (1961; “The Spear…

Bosnian-Croatian-Montenegrin-Serbian language: Groupings, geography, and religion: …three main groups, named Kajkavian, Chakavian, and Shtokavian after the pronoun meaning “what” (kaj, ča, and što or šta, respectively), though the three dialects also differ in vowels, consonants, word forms, and vocabulary. Serbia, Montenegro, and Bosnia and Herzegovina are entirely Shtokavian. Croatia uses Chakavian along the seacoast, Kajkavian in…

Motilón: Chief among them were the Chaké and the Mape, who were agricultural and forest-dwelling and hostilely resisted European encroachments well into the 20th century.

Chahar, eastern tribe of Mongols, prominent in the 15th and 16th centuries. The Chahar were part of the empire of Dayan Khan (1470–1543), the last great khan of a united Mongolia. After his death the khanate remained formally among the Chahar, although it was substantially weakened. The last

chakravartin, the ancient Indian conception of the world ruler, derived from the Sanskrit chakra, “wheel,” and vartin, “one who turns.” Thus, a chakravartin may be understood as a ruler “whose chariot wheels roll everywhere,” or “whose movements are unobstructed.” Buddhist and Jain sources

Chakkri Dynasty, Thailand’s ruling house, founded by Rama I, who, under the title of Chao Phraya Chakkri (military commander of the Chao Phraya area), had played an important role in the struggle against Burma. Chakkri became king of Thailand in 1782 following the execution of his predecessor. As

Rama I was a Siamese king (1782–1809) and founder of the Chakkri dynasty (q.v.), which reigns in Thailand. (Read Sir Walter Scott’s 1824 Britannica essay on chivalry.) Rama I was the son of a high court official and his part-Chinese wife. At the time of the Burmese invasion of Siam in 1766–67, he

Chakma, largest of the indigenous populations of Bangladesh, also settled in parts of northeastern India and in Myanmar (Burma). Their Indo-Aryan language has its own script, but the Chakma writing system has given way, for the most part, to Bengali script. The earliest history of the Chakma people

Alan Hovhaness was an American composer of Armenian and Scottish descent, notable for his eclectic choice of material from non-European traditions. Hovhaness studied composition with Frederic Converse at the New England Conservatory from 1932 to 1934 and in 1942 at the Berkshire Music Center in

Dagomba: …among them the Konkomba and Chakosi.

chakra, (“wheel”), any of a number of psychic-energy centres of the body, prominent in the occult physiological practices of certain forms of Hinduism and Tantric Buddhism. The whirling wheel-like disc called the Sudarshana Chakra is the spike-laden divine weapon of Vishnu, one of the principal

chakravartin: …three types of secular chakravartin: chakravala chakravartin, a king who rules over all four of the continents posited by ancient Indian cosmography (i.e., a universal monarch); dvipa chakravartin, a ruler who governs only one of those continents and is, therefore, less powerful than the first; and pradesha chakravartin, a monarch…

chakravartin, the ancient Indian conception of the world ruler, derived from the Sanskrit chakra, “wheel,” and vartin, “one who turns.” Thus, a chakravartin may be understood as a ruler “whose chariot wheels roll everywhere,” or “whose movements are unobstructed.” Buddhist and Jain sources

Chakkri Dynasty, Thailand’s ruling house, founded by Rama I, who, under the title of Chao Phraya Chakkri (military commander of the Chao Phraya area), had played an important role in the struggle against Burma. Chakkri became king of Thailand in 1782 following the execution of his predecessor. As

Rama I was a Siamese king (1782–1809) and founder of the Chakkri dynasty (q.v.), which reigns in Thailand. (Read Sir Walter Scott’s 1824 Britannica essay on chivalry.) Rama I was the son of a high court official and his part-Chinese wife. At the time of the Burmese invasion of Siam in 1766–67, he

Malawi: Malawi since 1994: …vote; he was followed by Lazarus Chakwera of the MCP, who obtained 27.8 percent, and Banda, who came in third with 20.2 percent. Banda conceded and Mutharika was sworn in as president on May 31, 2014.

Lake Hulun, large lake in the Hulun Buir Plain, northern part of the Inner Mongolia Autonomous Region, northern China. The lake is fed by two rivers that rise in Mongolia: the Kerulen (Kelulun), which flows from the west, and the Orxon (Orshun), which flows from the south. The surface area of Lake

César, duke de Vendôme: …in an unsuccessful plot (the Chalais conspiracy) in 1626 to assassinate Richelieu. As a result, he and his brother Alexandre, grand prior of France, were imprisoned at Vincennes. Alexandre died in prison (1626), and César was forced to resign Brittany before his release (1630).

Timothée Chalamet is an American actor known for his sensitive portrayals of complex characters in independent films and blockbusters and for his artful humor in ensemble comedies. Chalamet was raised in Manhattan, in an apartment that he shared with his mother, a former Broadway dancer and

Timothée Chalamet is an American actor known for his sensitive portrayals of complex characters in independent films and blockbusters and for his artful humor in ensemble comedies. Chalamet was raised in Manhattan, in an apartment that he shared with his mother, a former Broadway dancer and

Bangladesh: Relief: …vast marshy area called the Chalan wetlands, also known as Chalan Lake. The floodplains of the Jamuna, which lie north of the Bhar Basin and east of the Barind, stretch from the border with Assam in the north to the confluence of the Padma and Jamuna in the south. The…

Northern Mariana Islands: Early period: Archaeological evidence at Chalan Piao on Saipan indicates that the Northern Marianas were settled by an insular people originating in Southeast Asia. They made a distinctive form of red-slipped pottery, sometimes incised with lime-filled decoration, closely related to Philippine ceramics. By 800 ce a plain, unslipped pottery style…

Bangladesh: Relief: …vast marshy area called the Chalan wetlands, also known as Chalan Lake. The floodplains of the Jamuna, which lie north of the Bhar Basin and east of the Barind, stretch from the border with Assam in the north to the confluence of the Padma and Jamuna in the south. The…

Chalatenango, city, northern El Salvador. It lies along the Tamulasco and Cholco rivers at an elevation of 1,660 feet (506 metres). Originally an Indian settlement, it was placed under the Spanish colonial governor Carardalet in 1791 and was declared a town in 1847 and a city in 1871. The city’s

Hussein Chalayan is a Cypriot-British fashion designer best known for infusing intellectual concepts and artistic elements into his designs and shows. Chalayan was born to Muslim parents and attended Turk Maarif Koleji (“Turkish Education College”) in Cyprus. In 1978 he moved to England with his

sty: …sty is sometimes called a chalazion, although the latter term is usually reserved for a painless chronic swelling of the meibomian gland. A chalazion sometimes appears without apparent cause and sometimes as an aftereffect of an internal sty.

chalcanthite, a widespread sulfate mineral, naturally occurring hydrated copper sulfate, CuSO4·5H2O. It occurs in the oxidized zone of copper deposits and is frequently found on the timbers and walls of mine workings, where it has crystallized from mine waters. It was formerly an important ore

pre-Columbian civilizations: Olmec colonization in the Middle Formative: …largest of these sites is Chalcatzingo, Morelos, a cult centre located among three denuded volcanic peaks rising from a plain. On a talus slope at the foot of the middle peak are huge boulders on which have been carved Olmec reliefs in La Venta style. The principal relief shows an…

Chalcedon, ancient maritime town on the eastern shore of the Bosporus, opposite modern Istanbul, Turkey. A Megarian colony founded in the early 7th century bce is the earliest known settlement at the site. According to Herodotus, it became known as the “city of the blind” because the site was so

Council of Chalcedon, fourth ecumenical council of the Christian church, held in Chalcedon (modern Kadiköy, Turkey) in 451. Convoked by the emperor Marcian, it was attended by about 520 bishops or their representatives and was the largest and best-documented of the early councils. It approved the

chalcedony, a very fine-grained (cryptocrystalline) variety of the silica mineral quartz (q.v.). A form of chert, it occurs in concretionary, mammillated, or stalactitic forms of waxy lustre and has a compact fibrous structure, a fine splintery fracture, and a great variety of colours—usually

Native American art: Chile and Argentina: …where they were known as Chalchaquí. Very soon the peoples of this region developed their own arts, some of which are unique. They produced fine pottery and strong, colourful textiles. Gold was never a major product, although copper became an important metal, partly because of its prevalence. The people cast…

Chalchiuhtlicue, Aztec goddess of rivers, lakes, streams, and other freshwaters. Wife (in some myths, sister) of the rain god Tlaloc, in Aztec cosmology she ruled over the fourth of the previous suns; in her reign, maize (corn) was first used. Like other water deities, she was often associated with

Chalchiuhtlicue, Aztec goddess of rivers, lakes, streams, and other freshwaters. Wife (in some myths, sister) of the rain god Tlaloc, in Aztec cosmology she ruled over the fourth of the previous suns; in her reign, maize (corn) was first used. Like other water deities, she was often associated with

United Provinces of Central America: …defeated and killed at the Battle of Chalchuapa (April 2).

chalcid wasp, (superfamily Chalcidoidea), any of more than 22,000 species of rather small solitary wasps, the majority of which are parasitic as larvae. Some authorities believe that this superfamily may actually contain up to 100,000 species, although these have yet to be formally named. Taxonomy

Chalcidian alphabet, one of several variants of the Greek alphabet, used in western Greece (Évvoia) and in some of the Greek colonies in Italy (Magna Graecia); probably ancestral to the Etruscan alphabet. See Greek

Chalcidian League, (432–348 bc), confederacy of the Greek cities of Chalcidice in northeastern Greece directed at first against Athens and later, after the defeat of Athens in the Peloponnesian War, against encroachment by Macedonia. Founded by Olynthus as a league with complete equality and

Chalcidian alphabet, one of several variants of the Greek alphabet, used in western Greece (Évvoia) and in some of the Greek colonies in Italy (Magna Graecia); probably ancestral to the Etruscan alphabet. See Greek

Chalcidice, peninsula and a perifereiakí enótita (regional unit), Central Macedonia (Modern Greek: Kendrikí Makedonía) periféreia (region), northern Greece. It terminates in (east–west) the three fingerlike promontories of Kassándra, Sithonía, and Áyion Óros (Mount Athos). The promontories were

Platonism: Medieval Platonism: …4th century the Christian exegete Calcidius (Chalcidius) prepared a commentary on Plato’s Timaeus, which exerted an important influence on its medieval interpretation. A Christian Platonic theism of the type of which Boethius is the finest example thus arose; based on a reading of the Timaeus with Christian eyes, it continued…

chalcid wasp, (superfamily Chalcidoidea), any of more than 22,000 species of rather small solitary wasps, the majority of which are parasitic as larvae. Some authorities believe that this superfamily may actually contain up to 100,000 species, although these have yet to be formally named. Taxonomy

chalcid wasp, (superfamily Chalcidoidea), any of more than 22,000 species of rather small solitary wasps, the majority of which are parasitic as larvae. Some authorities believe that this superfamily may actually contain up to 100,000 species, although these have yet to be formally named. Taxonomy

Chalcis, city and dímos (municipality) on the island of Euboea (Évvoia), periféreia (region) of Central Greece (Modern Greek: Stereá Elláda), western Greece. It lies at the narrowest point (measured only in yards) of the Euripus (Evrípos) channel, which separates Euboea from the Greek mainland and

Kızıl Adalar: …islands, Büyükada (Prinkipo, ancient Pityoussa), Heybeli Ada (Halki, ancient Chalcitis), Burgaz Adası (Antigoni, ancient Panormos), and Kınalı Ada (Proti). Büyükada was Leon Trotsky’s home for a time after his exile from the Soviet Union in 1929. Heybeli Ada has a branch of the Turkish naval academy.

pre-Columbian civilizations: Agriculture: …chinampa, was first applied to Lake Chalco. The lake covered approximately 60 square miles and apparently varied in its character from swamps to ponds of fairly deep, open water. By a process varying from digging drainage ditches to artificial construction of land from lake mud and vegetation, most of the…

chalcocite, sulfide mineral that is one of the most important ores of copper. Valuable occurrences include deposits of sulfide minerals at Ely, Nev., and Morenci, Ariz., where other components of the original rock have been dissolved away; it is also found with bornite in the sulfide veins of

Laonicus Chalcocondyles was a Byzantine historian, the author of the valuable work Historiarum demonstrationes (“Demonstrations of History”). Chalcocondyles came of a distinguished Athenian family and was educated at the Palaeologan court at Mistra in the Peloponnese. His history is prefaced by a

oxygen group element, any of the six chemical elements making up Group 16 (VIa) of the periodic classification—namely, oxygen (O), sulfur (S), selenium (Se), tellurium (Te), polonium (Po), and livermorium (Lv). A relationship between the first three members of the group was recognized as early as

oxygen group element, any of the six chemical elements making up Group 16 (VIa) of the periodic classification—namely, oxygen (O), sulfur (S), selenium (Se), tellurium (Te), polonium (Po), and livermorium (Lv). A relationship between the first three members of the group was recognized as early as