February 21, 2017 If you thought that the cesium fountain atomic clock was the most accurate clock in the world, then think again. A newer and more stable clock, the Ytterbium lattice optical clock, has proven to be a hundred times more accurate and as such, it has the capability and is regarded as certain of redefining the SI second. Ytterbium was discovered by Jean Charles Galissard de Marignac, a Swiss chemist, in 1878 in Geneva Switerland. Named after Yterrby, a village in Sweden, it is one of nine elements discovered in the mineral yttria and one of four elements (yttrium, terbium, erbium, ytterbium) named after this town. Although other chemist such as Swiss chemists Lars Fredrik Nilson and Carl Gustaf Mosander, as well as, French …show more content…
It contains three allotropic forms – alpha, a hexagonal crystalline structure stable at low temperatures (-13 degrees Celcius); beta, a metallic electrical conductivity at normal atmospheric pressure and a semiconductor with pressures of 16,000 atm; and gamma, a body centered crystalline structure at high temperatures (795 degrees Celcius) (Hammond, 2000). According to the National Nuclear Data Center, there are approximately 39 known isotopes, seven which are stable (mass numbers 168, 170, 171, 172, 173, 174, and 176). Considered fairly stable, Ytterbium is kept in airtight containers to protect it from air and moisture, since it is known to tarnish quickly in air, reacts slowly with water, and dissolves rapidly in mineral acids. Although it poses no threat to plants and animals, metallic ytterbium dust poses a fire and explosion hazard and ytterbium is also considered a skin and eye …show more content…
Klemm and Bonner made the first metal by heating ytterbium chloride and potassium in 1937, and in 1953, Daane, Dennison, and Spedding produced pure metal. Since then, it has been utilized in alloys and with stainless steel to improve grain purification and strength, as catalysts in organic chemistry, in portable x-rays that need no electricity (Yb 160), in stress gauges to monitor ground formations during earthquakes/underground explosions, and as a fiber laser amplifier in marking and engraving. Yet possibly its most important use to date, is its “future redefinition of the SI second” based on the development of a new atomic clock utilizing ytterbium, the optical lattice clock (Physics/General Physics, 2013). Developed by scientists at the National Institute of Standards and Technology, the ytterbium lattice clock has proven a strong competitor to the now cesium fountain atomic
Just as the title of the chapter suggests, the main focus of Chapter 11 is how elements found on the Periodic Table are not always what they appear. Kean begins this chapter with describing how elements can be unpredictable in some conditions, and uses example from the past to...
Molybdenum is not found in nature, and the compounds that can be found were, until the late 1700s confused with other elements, such as carbon and lead. In 1778 Carl Wilhelm Scheele discovered that molybdenum was separate from graphite and lead, and was able to isolate the oxide of the metal from molybdenite. Molybdenum was rarely used and stayed in the laboratory until the late 19th century. Plants and animals generally have molybdenum, present in very small amounts.
Beryllium has the symbol Be. In the older chemical literature, beryllium is called glucinium after the Greek word glykys meaning sweet, because of Vauquelin's initial description and observation of Beryllium. Beryllium's atomic number is 4, its atomic weight is 9.01 and in its pure metal form it melts at 1278 degrees Celsius.
The mere presence of antisocial behavior is not sufficient to diagnose a person with antisocial personality disorder. In order to be diagnosed with this disorder one must display a pattern of violation of other's rights and of disrespectful behavior, which appear after the age of 15. This individual will also display some behavioral problems so called before the age of 15 such as conduct disorder. The individual must be at least 18 years old. The occurrence of antisocial behavior is not exclusively during the course of Schizophrenia or a Manic Episode. In addition, according to DSM-V diagnosis of antisocial personality disorder can be made only if a person meet at least the three of the following criteria's: 1) failure to comply with social norms that are related to lawful behaviors as indicated by repeatedly committed acts that are grounds for arrest; 2) Deceitfulness, dishonesty manifested in repeated lies, using false names and nicknames or cheating other people for their own benefit or pleasure; 3) Impulsivity or failure to plan ahead; 4) irritability and aggressiveness, as indicated by repeated participation in fights or assaults; 5) reckless disregard for own safety and the safety of others; 6) persistent lack of accountability, as indicated by repeated failure to maintain a permanent job or failing to meet financial obligations; 7) lack of remorse, as indicated by indifference to the infliction of harm others, beating them and stealing from them, or looking for the rationalization for such acts.
They new the structure and particle makeup of atoms, as well as how they behaved. During the 1930Õs it became apparent that there was a immense amount of energy that would be released atoms of Gioielli 2certain elements were split, or taken apart. Scientists began to realize that if harnessed, this energy could be something of a magnitude not before seen to human eyes. They also saw that this energy could possibly be harnessed into a weapon of amazing power. And with the adven...
Mr. Cronstedt discovered nickel in a mineral called niccolite. He originally planned to extract copper from this new mineral but got none at all. This is why nickel, at first, was called "false copper". Instead, Cronstedt got a silvery-white metal, which was eventually used for other things.
It was discovered by Sir Humphrey Davy in England, in 1807. Sir Davy was able to isolate potassium using electrolysis. Potassium was the first metal isolated by this procedure. Today, it is still not found free in nature. It is obtained by electrolysis of chloride or hydroxide.
Uuq-292 lost 3 neutrons, and afterwards the resulting isotope decayed further by alpha emission. 24494Pu + 4820Ca 292114Uuq 289114Uuq + 3(10n), this claims that superheavy elements can be made in the laboratory.
early 1990’s, no such material was known. In 1991, carbon nanotubes were discovered. Although not
In 1817, an aging Swedish chemist was pouring over his work on a late afternoon in Stockholm, Sweden. He was analyzing a strange ore named Petalite that had been procured from an island off the coast of Sweden called Utö. The ore Petalite (which is now recognized to be LiAl(Si2O5)2) had been discovered by a Brazilian scientist, José Bonifácio de Andrada e Silva towards the end of the 18th century on a visit to Sweden. This Swedish scientist, Johann August Arfvedson, detected traces of an unknown substance in his sample of Petalite. This was the first discovery of Lithium.
Uranium was discovered by Martin Heinrich Klaproth, a German chemist, in the mineral pitchblende (primarily a mix of uranium oxides) in 1789.Klaproth, as well as the rest of the scientific community, believed that the substance he extracted from pitchblende was pure uranium, it was actually uranium dioxide (UO2). After noticing that 'pure' uranium reacted oddly with uranium tetrachloride (UCl4), Radioactivity was first discovered in 1896 when Antoine Henri Becquerel, a French physicist, detected it from a sample of uranium. Today, uranium is obtained from uranium ores such as pitchblende, uraninite , carnotite and autunite as well as from phosphate rock , lignite (brown coal) and monazite sand . Since there is little demand for uranium metal, uranium is usually sold in the form of sodium diuranate , also known as yellow cake, or triuranium octoxide).
Sir Humphry Davy discovered potassium in 1807 in England, by isolating it using electrolysis. Potassium was the first metal to be isolated by using electrolysis. The name potassium originated from the English word "potash" meaning pot ashes and the Arabic word "qali" meaning alkali. This was because potassium was originally obtained by soaking wood ashes in water and then evaporating the mixture in an iron pot. The origin of the elements symbol “K” comes from the Latin word "kalium" meaning potassium. Potassium used to be called kalium, so the element symbol is 'K'.
The Periodic Table of Elements is commonly used today when studying elements. This table’s history begins in ancient times when Greek scientists first started discovering different elements. Over the years, many different forms of the periodic table have been made which set the basis for the modern table we use today. This table includes over 100 elements and are arranged by groups and periods. Groups being vertical columns and periods being horizontal columns. With all of the research conducted over the years and the organization of this table, it is easy to use when needed.
Though it was one of the three first elements (together with helium and hydrogen) to be synthesized in the Big Bang, lithium, together with beryllium and boron are markedly less abundant than other nearby elements. This is a result of the low temperature necessary to destroy lithium, and a lack of common processes to produce it.[34]
Kennedy, Gerry. "The Spectronics Blog." The Spectronics Blog RSS. Spectronicsinoz, 15 May 2012. Web. 04 Mar. 2014.