Aarushhh/wikipedia-simple-splitted huggingface dataset:
Events 
 February 10 – French and Indian War: The 1763 Treaty of Paris ends the war and France cedes Canada to Great Britain.
 15 February – the Treaty of Hubertusburg puts an end to the Seven Years' War between Prussia and Austria and their allies
 March 1 – Charles Townshend becomes President of the Board of Trade in the British government
 May 7 – Chief Pontiac begins the "Conspiracy of Pontiac" by attacking British forces at Fort Detroit.
 June 2 – Pontiac's Rebellion: At what is now Mackinaw City, Michigan, Chippewas capture Fort Michilimackinac by diverting the garrison's attention with a game of lacrosse, then chasing a ball into the fort.
 June 28 – earthquake in Komarom, Hungary
 August 5 – Pontiac's War – Battle of Bushy Run – British forces led by Henry Bouquet defeat Chief Pontiac's Native Americans at Bushy Run in the Pennsylvania backcountry.
The Treaty of Paris signed by Great Britain, France and Spain brings an end to the Seven Years' War (also called the French and Indian War in the United States)
 First publication of Bayes' theorem
 Proclamation of 1763

 

nv:1751 – 1800
1637 was a common year.

Events 
 February 3 – Tulip mania collapses in the United Provinces (now the Netherlands) by government order
 February 15 – Ferdinand III becomes Holy Roman Emperor
 December 17 – Shimabara Rebellion erupts in Japan
Pierre de Fermat makes a marginal claim to have proof of what would become known as Fermat's last theorem.
France places a few missionaries in the Côte d'Ivoire, a country it would come to rule more than 200 years later.
England wages war against the Mashantucket Pequots
 First opera house, Teatro San Cassiona, opens in Venice
 René Descartes – Discours de la Methode
Elizabeth Poole becomes the first woman to have founded a town (Taunton, Massachusetts) in the Americas.
Events 
 February 3 – Murad II, Sultan of the Ottoman Empire dies and is succeeded by his son Mehmed II.
 April 11 – Celje acquires market-town status and town rights by orders from the Celje count Frederic II.
 June 30 – French troops under the Comte de Dunois invade Guyenne and capture Bordeaux
 August 20 – The French capture Bayonne, the last English stronghold in Guyenne
 Foundation of the University of Glasgow
 Nicholas of Cusa invents concave lens spectacles to treat myopia
 Roger van der Weyden paints his Last Judgement
 Lodi dynasty succeeded the Sayyid dynasty in India

Births
 April 22 – Isabella of Castile
Events 
Change of era name from Yongxi (1st year) to Benchu era of the Chinese Han Dynasty
Change of emperor from Han Zhidi to Han Huandi of the Chinese Han Dynasty
Colima is a state in west Mexico.  About 760,000 people live there. Its capital is also called Colima.
Sir Peter Robert Jackson ONZ KNZM (born 31 October 1961, Wellington, New Zealand) is a New Zealand film director. He is most widely known for directing The Lord of the Rings film trilogy. He also directed the 2005 film, King Kong.

In 2003, Jackson won three Academy Awards for The Lord of the Rings: The Return of the King: Academy Award for Directing, Academy Award for Best Picture and Academy Award for Writing Adapted Screenplay.
Filmography 
 Bad Taste (1987)
 Meet the Feebles (1989)
 Valley of the Stereos (1992) (short film)
 Braindead (a.k.a. Dead Alive) (1992)
 Heavenly Creatures (1994)
 Forgotten Silver (1995) - mockumentary
 The Frighteners (1996)
 The Lord of the Rings: The Fellowship of the Ring (2001)
 The Lord of the Rings: The Two Towers (2002)
 The Lord of the Rings: The Return of the King (2003)
 King Kong (2005)
 The Lovely Bones (2007)
 Halo (2008) - executive producer
 The Adventures of Tintin - executive producer
 The Hobbit: An Unexpected Journey (2012)
 The Hobbit: The Desolation of Smaug (2013)
 The Hobbit: The Battle of the Five Armies (2014)

References

Other websites 

1961 births
Living people
Academy Award winning directors
Actors from Wellington
New Zealand movie actors
New Zealand movie directors
New Zealand movie producers
New Zealand screenwriters
Valencia is a city in Spain, on the Mediterranean coast. It is the capital of the Community of Valencia. It has 807.396 people, making it the third-largest city in Spain and the fifteenth in the European Union. 

Valencia has a borderline hot semi-arid climate (BSh in the Köppen climate classification) and a hot-summer Mediterranean climate (Csa in the Köppen climate classification).

Other websites 
Valencia Tourism Official Site

References 

Capital cities in Spain
Murcia is the capital of the autonomous community of Murcia, in Spain, and its biggest city, with a population of 420,000 in the city and more than 740,000 in the metropolitan area. The municipality is the seventh largest in Spain. 

The city is in the Segura Valley, in an area called la Huerta de Murcia, which is a very important agricultural center with oranges, lemons, tomatoes, onions, etc.; the varied fruits and vegetables typical of the Mediterranean lands. It has a hot semi-arid climate (BSh in the Koeppen climate classification). The city has a Baroque cathedral and a university.

Capital cities in Spain
Zaragoza (sometimes called Saragossa in English) is the capital of Aragon, in the Ebro Valley, in the crossroad from Barcelona, Valencia, Madrid, and Bilbao. The population is 643,000. The most important monument is the Nuestra Señora del Pilar (Basilica of Our Lady of the Pillar).

Zaragoza has a cold semi-arid climate (BSk in the Köppen climate classification) with hot summers and cool winters.

References 

Capital cities in Spain
Malaga (Spanish: Málaga) is a Spanish city in Andalusia, Spain on the Mediterranean coast. The city has 560,000 people. There are more than 1,000,000 people in the surrounding area. It is the second biggest city in Andalusia after Sevilla, and the sixth biggest in Spain. The 20th century artist Pablo Picasso was born in Málaga.

Málaga is southernmost large city in Europe, it lies on the Costa del Sol (Coast of the Sun) of the Mediterranean, about 100 km (62.14 mi) east of the Strait of Gibraltar and about 130 km (80.78 mi) north of Africa.
Málaga enjoys a subtropical–mediterranean climate. It has one of the warmest winters in Europe, with average temperatures of 17 °C (62.6 °F) during the day and 7–8 °C (45–46 °F) at night in the period from December through February.

Climate
Climate

The climate is subtropical-Mediterranean (Köppen climate classification: Csa) with very mild winters and hot summers. Málaga enjoys plenty of sunshine throughout the year, with an average of about 300 days of sunshine and only about 40-45 with precipitation annually. Its coastal location with winds blowing from the Mediterranean Sea make the heat manageable during the summer.
Málaga experiences the warmest winters of any European city with a population over 500,000. The average temperature during the day in the period December through February is . During the winter, the Málaga Mountains (Montes de Málaga) block out the cold weather from the north. Generally, the summer season lasts about eight months, from April to November, although in the remaining four months temperatures sometimes surpass . Its average annual temperature is  during the day  and  at night. In the coldest month, January, the temperature ranges from  during the day,  at night and the average sea temperature is . In the warmest month, August, the temperature ranges from  during the day, above  at night and the average sea temperature is .
Large fluctuations in temperature are rare. The highest temperature ever recorded at the airport is  on 18 July 1978. In the month of August 1881, the average reported daytime maximum temperature was a record . The coldest temperature ever recorded was  on the night of 4 February 1954. The highest wind speed ever recorded was on 16 July 1980, measuring . Snowfall is virtually unknown; since the end of the XIX century, Málaga city has only recorded snow one day in the 20th century, on 2 February 1954.

Annual average relative humidity is 65%, ranging from 58% in June to 72% in December. Yearly sunshine hours is between 2,800 and 3,000 per year, from 5–6 hours of sunshine / day in December to average 11 hours of sunshine / day in July. Rain occurs mainly in winter, with summer being generally dry. Málaga is one of the few cities in Europe which are "green" all year round.

References

Other websites 

 Málaga.diwiki.org  Periódico digital 

 
Capital cities in Spain
La Palma is another island of the Canary Islands

Las Palmas de Gran Canaria is the biggest city of the Canary Islands, in the Atlantic Ocean. The city, with a population of 383,308 in 2010, is the eighth-largest in Spain. 

Together with Santa Cruz de Tenerife, it is the capital of the Comunidad Autónoma de
Canarias (Autonomous Community of the Canary Islands). It is also the capital of the island of Gran Canaria and of the province of Las Palmas. The islands of this province are Gran Canaria, Lanzarote and Fuerteventura.

The city was founded in 1478. The town has a beautiful old area. This area (Vegueta) has a lot of houses from the 16th to the 19th Centuries. There is still a house where Christopher Columbus stayed in 1492. He stayed there before he went to the Americas. The interesting cathedral was begun in the year 1500.

Its port is one of the busiest in Spain and the biggest between Europe and Cape Town, in South Africa.
Las Palmas (for short) is famous for its very nice and dry weather all year round. It is also famous for its Las Canteras Beach. This beach is more than 3 kilometers long. The beach brings a lot of tourists to the city. 

Main industries: trade, tourism, canned food, fishing, shipbuilding.

Places to visit: Vegueta (old area); Triana (traditional commercial area); Playa de Las Canteras (Las Canteras Beach); cathedral; Casa de Colón (Columbus House); Museo Canario (archaeology museum); CAAM - Centro Atlántico de Arte Moderno (Modern Art Centre); Museo Élder de la Ciencia (science museum); Museo Néstor (museum with paintings); Teatro Pérez Galdós (theatre); Auditorio Alfredo Kraus (concert hall); Jardín Canario (Canary Garden, mostly with plants from the Canary Islands); Doramas Park.

Capital cities in Spain
Palma de Mallorca is the capital of the Balearic Islands and the Mallorca island, in the Mediterranean Sea, in front of the Iberian Peninsula. The city, with a population of 410,000, is the ninth-largest of Spain. It is a very important tourist center in the world, and is famous for its historic architecture. It has one university, a subway, and the international airport lies just southwest of the city.

Capital cities in Spain
Córdoba is a city in Andalusia, Spain. It is the capital of Córdoba province. It had a population of about 326,000 in 2017.

Córdoba was the capital of the Caliphate of Cordoba, an Islamic empire in the Middle Ages, when the city was the biggest in Europe, with 250,000 people.

Córdoba is 138 kilometers (86 miles) northeast of the city of Seville and is on the Guadalquivir river. Córdoba has a hot-summer Mediterranean climate (Csa in the Köppen climate classification) with the hottest summers of all European cities.

History
The Romans occupied Córdoba in 206 B.C. The city was very important in the 900s CE as a famous center of Moorish art and culture.  The Mezquita de Córdoba is the city's chief landmark. It was built as a mosque (Muslim house of worship) in the 700s and was made into a Roman Catholic cathedral in 1238.  More than 1,000 pillars of stone including granite, onyx, marble and jasper support its arches.
Economy
A soft, fine-grained leather called cordovan is made in Córdoba. Córdoba is the center of an agricultural region. The farms there produce grain, grapes, olives, and vegetables.

References 

 
Capital cities in Spain
Alacant or Alicante (, Valencian: ) is a city in Spain. It is the capital of the province of Alicante. It is in the southern part of the Valencian Community. It is also a historic Mediterranean port. The population of the city of Alicante proper is about 332,067, as of 2014, ranking as the second-largest Valencian city.  Including nearby municipalities, Alicante was populated by 458,843 residents. Population of the metropolitan area (including Elche and satellite towns) was 795,034 as of 2009. Based on population it is the eighth-largest metropolitan area of Spain.

The city is a sea port and a tourist centre. It has a hot semi-arid climate (BSh in the Koeppen climate classification).
The avenue Maisonnave is the principal commercial street in the city of Alicante. In fact, Maisonnave is the sixth most expensive avenue in the whole of Spain, which gives an idea of the importance that this  street has. The Corte inglés has in this central street both branches that it possesses in Alicant, one at each end of the avenue.

Santa Barbara's Castle is 166 metres up the Benacantil mountain. It's very strong with great strategic value. It's called Santa Barbara's Castle because the 4th of December is Santa Barbara's day and the 4th of December in 1248 is when it was taken from the Arabs by Alfonso of Castilla.

References

Other websites 
 Alicante Information 
 Interactive map

Capital cities in Spain
Phonology is part of linguistics. Linguistics is the scientific study of language. Phonology is the science that studies the way that sounds (phones) carry meaning in language. Sounds (phones) that carry meaning in language are called phonemes. Sounds that do not carry meaning in the language are called allophones.

Phonology focuses on the study of phonemes, "units of sound (speech) that distinguish one word from another in a particular language." Phonology also includes studies of how words are articulated, or spoken.

Terminology 
Phonology refers to the sound patterns of a language. Phonology is different from phonetics. Phonology studies how sounds form meaning in language. Phonetics studies how those sounds are formed. Studies of phonology and phonetics are sometimes combined, which results in more specific areas of study.
History 
In 300 BC, Panini was the first person to study phonology. He created a grammar (a set of language rules) for Sanskrit (an ancient Indian language). He also created a list of the phonemes in Sanskrit. He assigned a symbol to represent each phoneme. The symbols are still used today in phonology.

The first person to use the word "phoneme" was the French linguist (one who studies language) A. Dufriche-Desgenettes. In the 1800s, Jan Baudoin gave the definition of phoneme that is uses today.Soon afterward, Baudouin de Courtenay began the study of phonology.and worked on the theory of phonetic alternations, which predicts changes in the sounds of a language.

One of the best schools of phonology was the Prague school. In 1939, a student of that school, Prince Nikolai Trubetzkoy, published one of the most important studies on phonology. His work was titled Principles of Phonology. Another important person in the Prague school was Roman Jakobson. Roman was the most well-known linguist in the 1900s.
In 1968, Noam Chomsky and Morris Halle published The Sound Pattern of English (SPE). This book described generative phonology, which studies how grammar changes how people use language.

Branches of linguistics
Linguistics is the study of language. People who study language are called linguists.

There are five main parts of linguistics: the study of sounds (phonology), the study of parts of words, like "un-" and "-ing" (morphology), the study of word order and how sentences are made (syntax), the study of the meaning of words (semantics), and the study of the unspoken meaning of speech that is separate from the literal meaning of what is said (for example, saying "I'm cold" to get someone to turn off the fan (pragmatics).
Specialties 
Linguistics, in its broader context, includes evolutionary linguistics, which considers the origins of language; historical linguistics, which explores language change; sociolinguistics, which looks at the relation between linguistic variation and social structures; psycholinguistics, which explores the representation and function of language in the mind; neurolinguistics, which looks at language processing in the brain; language acquisition, how children or adults acquire language; and discourse analysis, which involves the structure of texts and conversations.
Although linguistics is the scientific study of language, a number of other intellectual disciplines are relevant to language and intersect with it. Semiotics, for example, is the general study of signs and symbols both within language and without. Literary theorists study the use of language in literature. Linguistics additionally draws on and informs work from such diverse fields as acoustics, anthropology, biology, computer science, human anatomy, informatics, neuroscience, philosophy, psychology, sociology, and speech-language pathology. Discourse analysis is the study of entire conversations or texts. 

Many linguists compare languages to find similar properties. That makes it possible to find things shared by all the languages of the world and also learn the languages that are related in a language family. Linguists who study how languages are structured and how they work are said to study theoretical linguistics.
Another part of linguistics is involved in understanding how languages are used in society or in the world. Sociolinguistics studies how language is used in society, and historical linguistics studies how languages change over time and how languages were in the past. One part of historical linguistics is etymology, the study of the history of words.

The part of linguistics that aims to find out how language works in the mind is known as psycholinguistics.

History

The study of language began in India with Pāṇini, the 5th century BC grammarian who wrote about the 3,959 rules of Sanskrit grammar, which described the different kinds of vowels and consonants of Sanskrit as well as its verb and noun classes. In the Middle East, Sibawayh (سیبویه) wrote a book about Arabic in 760 AD, Al-kitab fi al-nahw (الكتاب في النحو, The Book on Grammar) and was the first known author to talk about the difference between sounds and phonemes.
Linguistics started in the West as early as it did in the East, but Western linguistics at that time was more like philosophy and less the study of language. Plato was the first western philosopher to write about semantics in his Cratylus in which he argues that words represent concepts that are eternal and exist in the world of ideas. The word etymology is first used to talk about the history behind a word's meaning.

For many centuries most linguistic work was "philology".

References
1636 was a leap year starting on Tuesday of the Gregorian calendar.

Events 
 March 26 – Utrecht University is founded in the Netherlands.
Harvard University founded.
 In the American colonies, Roger Williams (theologian) founds Rhode Island.
 The first American ancestor of John Adams, Henry Adams, emigrates to Massachusetts.
711 was a common year in the 8th century.

Events 
The Moors begin to control Spain.
The Arabs begin to control Southern Pakistan.
Segura is a Spanish river that is 325 kilometers (200 miles) long. It flows through the provinces of Jaen, Albacete, Murcia, and Alicante, and the cities of Cieza, Molina de Segura, Murcia, Orihuela, Rojales, and Guardamar. It then flows into the Mediterranean Sea.

Rivers of Spain
Orihuela is a city on the coast in Spain in the Alicante province, on the Segura river in a district called Vega Baja. Oranges and lemons are grown. The city has a population of 75,000 with very important historical monuments like the Cathedral and the church of Santiago, the church of Santa Justa and Rufina and the Seminarium.

Cities in the Valencian Community
Municipalities in the Valencian Community
Province of Alicante
Alacant () province is the fifth largest Spanish province by population with 1,750,000, and the second largest in the Valencian Community. It is on the south-east Mediterranean coast and the capital is the city of Alicante, a sea- port with a university. It is a commercial city with monuments like Sainte Barbra Castle. Other important cities are Elche, 215,000 with palms trees and its important shoe industry; Torrevieja, 100,000, tourist centre with the world-famous Habaneras contest; Orihuela, 75,000, agricultural important center; Benidorm, 67,000, the Mediterranean Manhattan; Alcoi, 60,000; textile center, and Elda, 55,000, shoes industry.

The most important river is the Segura, in the south, which provides the water to Alicante, Elche, Torrevieja, Orihuela and other cities. There are others like Vinalopo, Serpis, Amadorio, Ravine of the Sheeps and Monnegre.
The biggest mountain is Aitana, and other mountains are Mariola, Puig Bell, Maigmo and Gold Head, near Alicante. In the coast there are islands, the most important is Tabarca, and other is the Benidorm island. An important coast success is the Penon of Ifach, in Calpe.

The activities in Alicante province are tourism, industry (shoes, carpets, plays, dolls, textiles) and modern agriculture of regadium (oranges, lemons, tomatoes, almonds, wine). There are two universities: University of Alicante and University of Michael Hernandez.
Turkmenistan ( or ; , ;), also known as Turkmenia, is a country in South-Central Asia. It has borders with Afghanistan, Iran, Kazakhstan, Uzbekistan. It has no ocean but it is on the Caspian Sea to the west.  The capital of Turkmenistan is Ashghabat.
The majority of the country is Muslim at 93%.

Turkmenistan is a non-aligned and fully neutral country.

History 
Turkmenistan was part of the Soviet Union since its creation, in 1922. At first, Turkmenistan was an autonomous republic within Russian SFSR. In 1925 it was promoted to a Soviet republic. Turkmenistan is an independent country since 1991, after the breakup of the Soviet Union. Saparmurat Niyazov became Turkmenistan’s first president in 1991.

Provinces
Turkmenistan is divided into five provinces and one capital city district. The provinces are divided into districts which may be either counties or cities.
Climate
Turkmenistan is one of the driest desert areas in the world. Some places have an average annual precipitation of only . The highest temperature recorded in Ashgabat is . Kerki, an extreme inland city located on the banks of the Amu Darya river, recorded  in July 1983, but this value is unofficial. 50.1C is the highest temperature recorded at Repetek Reserve, recognized as the highest temperature ever recorded in the whole former Soviet Union.

Geography
Turkmenistan is the world's 52nd-largest country. It is slightly smaller than Spain and somewhat larger than the US state of California. Over 80% of the country is covered by the Karakum Desert.

The Turkmen shore along the Caspian Sea is  long. The Caspian Sea is entirely landlocked, with no access to the ocean.

The major cities include Aşgabat, Türkmenbaşy (formerly Krasnovodsk) and Daşoguz.
Turkmenistan has a humid climate. Annual rainfall is low, particularly in summer. Winters are dry and mild. The wettest region in Turkmenistan is Köýtendağ Range. Köýtendağ is in southeastern Turkmenistan on the borders with Uzbekistan.

References 

 Turkmenistan
Members of the Organisation of Islamic Cooperation
Current dictatorships
Caesium (or cesium) is the chemical element with the atomic number 55 on the periodic table. Its symbol is Cs.

Caesium is an alkali metal. Its melting point is low (28 °C). It is extremely reactive. Because of its high reactivity, it is a dangerous chemical. It may set itself on fire (ignite) in air. It explodes on contact with water. It reacts more violently than the other alkali metals with water. Because of this, caesium is stored in mineral oil.

Caesium is a rare element. Since there is little caesium on the Earth, it is rather expensive. The human body does not need caesium. In large amounts, its chemical compounds are mildly poisonous because it is close to potassium, which the body does need.
History 
Caesium was first described in 1860, by Gustav Robert Kirchhoff and Robert Wilhelm Bunsen. They were testing mineral water, from Bad Dürkheim. After they separated calcium, strontium, magnesium and lithium, they saw two lines in the "blue" range of the spectrum. Because of these lines, they concluded that in addition to the elements already found, there must be another unknown substance in the mineral water. They named this substance caesium, after the color blue.

Isotopes and compounds 
Caesium has at least 39 known isotopes ranging in atomic mass from 112 to 151. Only one of these, Cs, is stable. Therefore, the naturally-occurring isotope of caesium is Cs, which is not radioactive. Cs is used in atomic clocks, its vibration frequency used to define the length of the second. Another isotope, Cs is not made naturally but is made after nuclear fission has been done. It is very radioactive and used as an industrial gamma ray source.
Caesium forms compounds with many other chemical elements. Caesium formate is used in oil drilling because of its high density.

Reactivity 
Caesium is extremely reactive in air and water. Caesium rapidly oxidizes in air and can spontaneously combust (randomly catch on fire) at any moment. For this reason, it must be stored in kerosene or a mineral oil, like other group one elements (Lithium, Natrium, Rubidium, and Francium.) In water, Caesium violently reacts to make Caesium Hydroxide (2CsOH).  The Caesium sinks for about one second, then explodes. The explosion is over 50 times the size of the element dropped in the water, and the explosion is enough to break a common Pyrex Beaker, Flask, or Test Tube.  You can find a video of the reaction here.

References

Alkali metals
Rubidium is chemical element 37 on the periodic table. Its symbol is Rb. Its atomic mass is 85.47. It has 37 protons and 37 electrons. It is a soft silver colored metal. It was first discovered in 1861 by Robert Bunsen and Gustav Kirchoff in Heidelberg, Germany.

Properties

Physical properties
Rubidium melts at a very low temperature, for example it could melt in a person's hand. Rubidium is an alkali metal. It can make an amalgam with mercury.

Chemical properties
Rubidium is very reactive. It will ignite in air because it reacts with many other elements in the air like oxygen and nitrogen. Rubidium reacts very violently with water to make hydrogen and rubidium hydroxide, a strong corrosive base. The reaction is normally very hot so the hydrogen ignites.

Chemical compounds
Chemical compounds

Rubidium forms chemical compounds in only one oxidation state: +1. Some rubidium compounds have a mixed oxidation state, though. Rubidium chloride is the most common rubidium compound. Rubidium hydroxide and rubidium carbonate are also used commonly. Rubidium compounds makes a red-violet color in a flame. Most rubidium compounds are colorless. Rubidium compounds are not as common as other alkali metal compounds, such get sodium compounds. Otherwise, they are similar.

Rubidium chloride, similar to sodium chloride
Rubidium hydride, strong reducing agent
Rubidium hydroxide, powerful base
Rubidium nitrate, strong oxidizing agent
Rubidiumoxide, yellow, strong base when dissolved in water
Occurrence and preparation
Rubidium is about as common as zinc. It is the 23rd most common element in the Earth's crust. Most minerals only have a small amount of rubidium in them. It normally comes in small quantities in other minerals. It is made by reduction of rubidium ores with calcium. It is expensive because calcium is difficult to make and the rubidium needs to be kept in argon and away from water or air.

Uses
There are not many common uses for rubidium. Rubidium compounds are sometimes used in purple fireworks. It and its compounds are used mainly in science research though. It is also used to make superoxide ions. It is used in some special types of glass.

Safety
Rubidium compounds are not very dangerous in the human body; however, if a person gets too much from eating, they could get sick because it acts like other alkali metal ions such as sodium ions in sodium chloride. Rats can live with up to half of their potassium replaced with rubidium, though it is not likely for that to happen.
Rubidium metal is very dangerous. It reacts with air and water and makes the corrosive substance rubidium hydroxide.

References

Alkali metals
Barium is chemical element 56 on the periodic table. Its symbol is Ba. It contains 56 protons and 56 electrons. Its mass number is about 137.3. It is a metal.

Properties

Physical properties
Barium is part of a group of elements known as the alkaline earth metals. It is a silvery metal that easily turns black. It is soft and ductile. It can form alloys with some metals that are partially alloys and partially chemical compounds.

Chemical properties
Barium is reactive, and if you put pure barium metal in the air, it will react with oxygen. At first it will turn black, then white as barium oxide is formed. Barium reacts with water to make barium hydroxide and hydrogen gas. Barium also reacts very fast with acids to make a barium salt and hydrogen. Barium can form barium peroxide if it is burned in air. 

Barium reacts with many other metal oxides and sulfides to make barium oxide or sulfide and the metal. It also reacts with carbon and nitrogen at a high temperature to make barium cyanide.

Chemical compounds
Chemical compounds

Barium is too reactive as a metal, so it is not found in the earth as a metal. It is found in chemical compounds. Barium only occurs in one oxidation state: +2. Most barium compounds are colorless. The ones that dissolve in water or stomach acid are very toxic. Barium sulfate is well known because it does not dissolve in water or acids. Barium compounds are quite heavy. Barium compounds put out a greenish flame when heated red-hot.

Occurrence

Barium is found as barium sulfate (barite) and barium carbonate (witherite) in the ground. Both of these minerals do not dissolve in water. Barium sulfate hardly dissolves in anything. Barium is found mainly in China, Germany, India, Morocco, and the US.
Preparation
It is very hard to get barium from barium sulfate. So barium sulfate is reduced by carbon to make barium sulfide and carbon dioxide. The barium sulfide is dissolved in hydrochloric acid. This makes hydrogen sulfide and barium chloride. The barium chloride is melted and electrolyzed to get liquid barium metal. The barium metal is solidified and stored in oil.

Barium carbonate, the other ore of barium, is dissolved in hydrochloric acid to make barium chloride and carbon dioxide. The barium chloride is melted and electrolyzed, making barium metal.

Uses

As a metal
Barium is used to remove oxygen from cathode ray tubes and vacuum tubes. It is placed inside and reacts with all of the oxygen, using it up. Barium is also used in spark plug wire.
As chemical compounds
Certain  compounds of barium, such as barium sulfate, are not toxic and can be put in the body. We can see where the barium travels in the body by X-rays and this can tell us whether there are problems, such as blockages. The barium sulfate builds up inside the body accumulating in organ systems. Barium sulfate absorbs the X-Rays as they pass through the body and an image is formed from the points where the rays have not passed through. It is useful because it provides a reasonably detailed image from very limited radiation exposure, compared with a CT scan for instance. Barium sulfate can be used as a pigment, too.

Other barium compounds have several other uses.
Safety
Barium is a very toxic element, and is dangerous. There is a really small amount of barium in our food, and this does not cause problems. If we get barium from other places, though, it can cause many problems. Even 1 gram of barium can kill you. It is dangerous because it acts like other really important elements, such as calcium and magnesium. If barium replaces these elements, it messes up the body.

References

Alkaline earth metals
Scandium is chemical element number 21 on the periodic table.  Its symbol is Sc.

Scandium is a metal in a group known as the transition metals.  It is also a rare earth metal.  What this means is that there is not very much scandium found in the earth.  Because of this, the pure metal can be expensive.  The pure metal is very reactive, and will react with other elements like oxygen.  The metal turns from shiny to gray.

Scandium is not very dangerous because there is not much of it on Earth, so there is not enough of it to harm us.  It does not have many uses. Its main use is perhaps as a component in Mercury-vapor lamps. Such lamps are used to light Stadiums.

Related pages
Periodic table
List of common elements

Transition metals
Vanadium is chemical element 23 on the periodic table. Its symbol is V. It is named after Vanadis, another name of Freyja.

Vanadium is a metal and is part of the group known as the transition metals. It is mostly used in steel where it helps strengthen the steel metal.

Vanadium is often found in aquatic forms of life. The human body may need a little bit of vanadium, but scientists are not sure.

Vanadium can react with a variety of other elements, and the chemical compounds it forms often have beautiful colors.

The amount of vanadium in the universe is 0.0001%, making the element nearly as common as copper or zinc. Vanadium is detected by spectroscopy in light from the Sun, and sometimes in light from other stars.
Vanadium is an element that is widely distributed in Earth's crust as well as in seawater and groundwater reservoirs. Therefore, it exerts great influence on the issues related to life and the environment. Vanadium is utilized by several marine organisms. For example, there are vanadate-dependent haloperoxidases in algae and several bacteria (e.g. Azotobacter) use it for nitrogen fixation and bacterial reduction involves the conversion of vanadate to oxide vanadium (IV).
With an average concentration of 35 nM, vanadium (V) (essentially present in the form of ion pairs Na+H2VO4-) is the second-to-most abundant transition metal in seawater, outclassed only by molybdenum (present as molybate MoO42-, ca. 100 nM). Vanadate-dependent haloperoxidases (VHPOs) can be present in marine brown, green, and red, algae, in (symbiotic) marine cyanobacteria, in Streptomyces bacteria, and in terrestrial fungi and lichen. Since the discovery of the first representative of these haloperoxidases and the bromoperoxidase VBrPo of the brown algae Ascophyllum nodosum, also known as wrack or pigweed, a plethora of macroalgae has been reported to have available VHPOs hence haloperoxidases that contain vanadate H2VO4- coordinated to a histidine residue in the enzyme's active center, and thus clearly distinct from the more common heme- based and non-heme peroxidases.
The budget of dissolved vanadium in the oceans is remarkably well balanced, with about 40x109 g V/y to 50x109 g V/y inputs and outputs, and a mean residence time for dissolved V in seawater of ~130,000 y with respect to inputs from rivers. Inputs and outputs are as follows: continental dust, 155x109 g V/y; sea spray, 0.52x109 g V/y; volcanic emissions, 7x109 g V/y; biomass burning, 5x109 g V/y; natural, 3.7x109 g V/y; human-induced, 4.1x109 g V/y; fossil fuel combustion, 100-287x109 g V/y; ratio anthropogenic: natural, 0.59-1.71.
Vanadium isotopes can be significantly fractionated during the delivery, cycling, and burial in the ocean. Temporal variations of 51V in seawater could be controlled by the aforementioned isotope fractionation and fluxes of various V sources and sinks to the ocean which is likely related to the global redox state of the oceans. A possible mechanism for the V isotopic offset between seawater and hydrogenous Fe-Mn crusts and nodules is the fractionation during the adsorption of V on the surface of the Fe-Mn oxyhydroxide.

Earth's crust
Vanadium is the 22nd most common element in the Earth's crust. Metallic vanadium is rare in nature. However, vanadium compounds occur naturally in about 65 different minerals. Much of the world's vanadium production comes from vanadium-bearing magnetite found in ultramafic gabbro rocks. Vanadium is mined mostly in South Africa, north-western China, and eastern Russia. In 2013 these three countries mined more than 97% of the 79,000 tonnes of produced vanadium.
Vanadium is also in bauxite and in deposits of crude oil, coal, oil shale and tar sands.

References 

Transition metals
Events 
 Rhodri the Great becomes King of Gwynedd.
 Louis II is crowned Holy Roman Emperor.

Births 
 Judith Martel

Deaths 
 January 25 – Pope Gregory IV
Arsenic is chemical element 33 on the periodic table.  Its symbol is As. Its atomic number is 33 and its atomic mass is 74.92. It is in the pnictogen group on the periodic table.

Properties

Physical properties
Arsenic is found in three allotropes. Gray arsenic is the most common. It is a brittle, somewhat soft metalloid that is a little shiny. It has a density of 5.73g/cm3. It is a semiconductor. Yellow arsenic is unstable and rare. It is the most toxic allotrope. It is a soft and waxy nonmetal, similar to white phosphorus. It turns into gray arsenic in light. Its density is 1.97g/cm3, much lighter than gray arsenic. It is created when arsenic vapor (made by heating arsenic very hot) is cooled very fast by something like liquid nitrogen. Black arsenic is similar to red phosphorus. It is a brittle, black, and shiny nonmetal. It does not conduct electricity. Since gray arsenic is the most common, it is usually referred to as arsenic.
Arsenic is found as one stable (nonradioactive) isotope, 75As. There are about 33 radioactive isotopes found. The longest lasting one is 73As, which has a half life of about 80 days.

Chemical properties

Arsenic is a relatively chemically inert element, similar to copper in reactivity. It burns in air to make garlic-smelling arsenic trioxide. Arsenic, as well as some of its compounds, do not have a liquid state; they sublime. Arsenic reacts with fluorine to make arsenic pentafluoride. It reacts with the rest of the halogens to make the arsenic trihalides. Arsenic does not dissolve in hydrochloric acid. It dissolves in concentrated nitric acid to make arsenic acid and in dilute nitric acid to make arsenious acid. It reacts with concentrated sulfuric acid to make arsenic trioxide. Arsenic burns with a pale lavender flame.

Chemical compounds
Chemical compounds

Arsenic forms chemical compounds in three oxidation states: -3, +3, and +5. -3 compounds are reducing agents. They are the main form of arsenic in the ground (as arsenides). Arsine is a colorless, highly toxic gas with a garlic odor. The +3 state is the most common. They are weak oxidizing agents. Arsenic trioxide is a white solid. It dissolves in water to make a solution of arsenious acid. The arsenic trichlorides are low melting covalent solids. The +5 state is common, too. They are strong oxidizing agents. Arsenic pentafluoride, a colorless and highly reactive gas, is the only stable arsenic pentahalide. Arsenic pentoxide dissolves in water to make arsenic acid, which can make arsenate salts.

-3 compounds
-3 compounds are reducing agents. They are found as arsenides and arsine. The metal arsenides have properties between an alloy and a salt.

Aluminium arsenide
Arsenide, the ion
Arsine, colorless highly toxic flammable gas
Gallium arsenide, used in LEDs
Zinc arsenide
+3 compounds
+3 compounds are weak oxidizing agents. Many are colorless, although some are orange.
Arsenic tribromide, white solid
Arsenic trichloride, colorless liquid
Arsenic trifluoride, colorless liquid
Arsenic triiodide, red-orange solid
Arsenic trioxide, white solid
Arsenic trisulfide, yellow solid

Arsenites
Arsenites are salts of arsenious acid.
Arsenious acid, weak acid
Arsenite, the ion
Paris green, copper acetoarsenite (copper acetate arsenite), green solid
Potassium arsenite
Sodium arsenite

+5 compounds
+5 compounds are strong oxidizing agents.
Arsenic pentafluoride, colorless gas
Arsenic pentoxide, white solid

Arsenates
Arsenates are salts of arsenic acid.
Arsenate, the ion
Arsenic acid, white solid or colorless solution
Lead arsenate
Potassium arsenate

Occurrence
Occurrence

Arsenic is found sometimes as an element in the ground, but is normally found in minerals. Some arsenic minerals have a metal and sulfur along with arsenic. Arsenopyrite is iron arsenic sulfide. It is the same as pyrite with arsenic added. Other arsenic minerals have a metal and arsenic. Erythrite, a cobalt arsenide mineral, is an example. Other arsenic minerals are simple. Realgar and orpiment (arsenic sulfides), simple arsenic minerals, are ores of arsenic.

Arsenic is found as a less toxic variety in fish and mushrooms. Some people think that humans need very small amounts of arsenic to be healthy. Some bacteria can use arsenic instead of phosphorus for some things; they are called arsenic bacteria.

Preparation

Most arsenic is made from the waste products after other metals are processed. Only China actually mines arsenic.
Arsenic is made from arsenopyrite by heating it. This makes arsenic trioxide which sublimes (along with sulfur dioxide), while the iron oxide stays behind. The arsenic trioxide is condensed, while the sulfur dioxide does not condense. The arsenic trioxide can be reduced with carbon. Another way is to heat the arsenopyrite without air. Then gray arsenic is made. Realgar can be heated to make arsenic trioxide as well.

History
Arsenic was known since antiquity. It was alloyed with bronze to make the bronze harder. Some people used arsenic as make-up, although it was toxic. Arsenic was well known as a poison. Since people used it to kill royalty and it was hard to detect, it was called the "Poison of Kings" and the "King of Poisons". An arsenic compound could have been the first organometallic compound (a metal bonded to an organic compound).
Uses
Arsenic compounds were used as a preservative for wood. Once people saw how toxic arsenic was, they stopped using it to preserve wood. Some feed for animals had arsenic in it to prevent disease. Lead arsenate was used as an insecticide in orchards but damaged the brains of those who put the insecticide on the trees.

Arsenic was used in medicines in the 1700s, 1800s, and 1900s. Arsenic trioxide was used to treat cancer. Very tiny doses of arsenic compounds can act as stimulants. Some arsenic compounds are used as poison gases. 

Arsenic as an element is used in alloys. The lead in lead acid batteries has some arsenic in it to make it stronger. Some semiconductors have arsenic in them.

Copper arsenate was used as a coloring for sweets. Paris green, a green pigment having arsenic in it, made many people sick. Some bullets have arsenic in them. Arsenic is sometimes added to brass to prevent the zinc from coming out. Arsenic was used in optical glass but was taken out because it was toxic.
Safety
Arsenic and its compounds are highly toxic. They are carcinogens. Water near arsenic mines is normally contaminated with arsenic. Wood that was preserved with arsenic compounds can leach arsenic into the soil. Emissions from coke ovens have arsenic in them.

Semimetals
Manganese is chemical element 25 on the periodic table. Its symbol is Mn. (Some people get it confused with magnesium, the symbol is Mg). Manganese is used a lot in steel to make it stronger. This is the main use for manganese metal. Manganese compounds, particularly manganese(IV) oxide, are used in alkaline cells and Leclanche cells. Manganese metal is also alloyed with aluminium.

Our bodies and plants need manganese to work right. If we do not get enough manganese, we can get sick. We get manganese from our food and vitamins also have some manganese to make sure that we get enough. It has 25 protons. Its mass number is 54.94.

Properties
Properties

Manganese is a silvery-gray metal and is part of the group known as the transition metals. It is similar to iron. It is hard to melt, but easy to oxidize. Manganese forms chemical compounds in several oxidation states: +2, +4, and +7 are the most common. Manganese compounds can be black, brown, pink, red, green, blue, and purple. Manganese(II) compounds are pink or light brown. They are unreactive. Manganese(II) chloride is a common example. Manganese(III) compounds are weak oxidizing agents. Manganese(IV) compounds are stronger oxidizing agents, but they are rarer. They are normally black in colour. Manganese(IV) oxide is an example.

Manganese(V) compounds are not stable and disproportionate easily. They are bright blue. They are very rare. Hypomanganates are the most common manganese(V) compounds. Manganese(VI) compounds are made in the process used to make permanganates. They disproportionate too. Manganates are weak reducing agents and moderate oxidizing agents. They are bright green.
Manganese(VII) compounds are purple-black and are powerful oxidizing agents. Permanganates contain the MnO4- ion. They are normally purple-black and strong oxidizing agents. Potassium permanganate is an example.

Isotopes 
Manganese that is found in nature is made up of one stable isotope, which is manganese-55. Manganese has many radioisotopes ranging from manganese-44 to manganese-69. The most stable radioisotope is manganese-53. It has a half-life of 3.7 million years.

Occurrence
The Earth's crust contains about 1000 ppm of manganese. It is the 12th most abundant element in the Earth's crust. Soil contains 7–9000 ppm of manganese. Seawater only contains 10 ppm of manganese. The atmosphere contains 0.01 µg/m3 of manganese. Manganese mainly occurs as pyrolusite, braunite, psilomelane.
Manganese is sometimes found alloyed with iron naturally. These rocks, called meteorites, came from space. Pyrolusite is one of the main sources of manganese. It also occurs as manganese carbonate. Some silicates have manganese in them. The derivation of Manganese may have come from either the Latin 'magnes', meaning magnet, or from the black magnesium oxide, 'magnesia nigra'.

Preparation
Manganese is normally made in an alloy with steel. This is made by mixing manganese ore and iron ore in a furnace and reducing it with carbon. This forms an alloy called ferromanganese. Pure manganese is made by reacting the manganese ore with sulfuric acid and electrolyzing it.

Our bodies and plants need manganese to work right. If we do not get enough manganese, we can get sick. We get manganese from our food and vitamins also have some manganese to make sure that we get enough.
Uses 
Manganese is used to make cheap stainless steel. Methylcyclopentadienyl manganese tricarbonyl is used as an additive in gasoline that does not have lead to reduce engine knocking.

Manganese(IV) oxide is used as a reagent in organic chemistry for the oxidation of benzylic alcohols. Manganese dioxide is also used in the manufacture of oxygen and chlorine. It is also used to dry black paints. Sometimes, it is used as a brown pigment for paint. It is a component of natural umber.

Manganese compounds have been used as pigments to color ceramics and glass. Tetravalent manganese is used as an activator in phosphors that glow red. Manganese oxide is also used in Portland cement mixtures.

Biological role 

There are lots of classes of enzymes that have manganese cofactors. They are oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases, lectins, and integrins. The reverse transcriptases of many retroviruses contain manganese.
Biological role in humans 
Manganese is an essential nutrient. It is found as a coenzyme in many biological processes. They include macronutrient metabolism, bone formation, and free radical immune system. It is a very important component in lots of proteins and enzymes. The human body contains about 12 mg of manganese. Manganese is found in the bones, liver, brain and kidneys. In the human brain, the manganese is bound to manganese metalloproteins.

Biological role in plants 
Manganese is also important in the photosynthetic oxygen evolution in the chloroplasts of plants. The oxygen-evolving complex is a part of photosystem II. The photosystem ll is found in the thylakoid membranes of chloroplasts. It is responsible for the photooxidation of water during the light reactions of photosynthesis. It has a metalloenzyme core that has four atoms of manganese.