who discovered radioactivity and how was it discovered?
445826
some heavy materials emits the rays in spontaneously this is called radioactivity. this is accidentally found by Henry Becquerel
65491
radioactivity is caused by a instability in the forces holding the nucleus of an atom. A atom emits radiation to allow it to change into a more stable element or isotope.
1057305
Polonium was discovered by Maria Skłodowska-Curie and her husband Pierre Curie in 1898 and was later named after Marie's home land of Poland.
160073
Joseph Priestley is best known as the discoverer of oxygen.\nHe isolated 'depholgisticated 'air, or 'good air' in 1774. Our understanding today of the chemical reaction of oxygen comes from Antoine Lavoisier's systematic theory of combustion.\n\nToo bad contributors like the above 'opinion' can't use this forum as a means of increasing knowledge, rather than \ngiving silly answers in order to get points. Some never grow up i suppose.\nSource:www.woodrow.org./teachers/chemistry/institutes/priestley.
782015
The MOST recently discovered element was atomic number 118.  It is being temporarily called 'ununoctium'.  As to WHEN it was discovered... that's a little more complicated.\n\nA team of element-makers at Lawrence Berkeley lab claimed to have made it in 1999, but when nobody could reproduce the find with the lab's methods (even the original lab), their finding was discredited.\n\nIn Spring of 2002 (it took four months) the Joint Institude of Nuclear Research in Dubna claimed to have produced an atom of ununoctium.  This was confirmed by Dubna and the Berkeley lab when each of them produced another atom in 2005.\n\nThe average lifespan of these three atoms was just under a thousandth of a second.  So don't expect any accumulation of the stuff!
2825
Most of the elements have been either discovered by scientists or created by scientists.  Only a choice few have been known since antiquity -- usually ones that are found in their elemental state in nature or are easy to isolate from compounds (usually ores).  These are iron, copper, tin, lead, silver, gold, and mercury.  \n\nSome of the elements were discovered by people you might not consider scientists.  For example, Albertus Magnus was the first to isolate arsenic.  He was a theologian and philosopher in the 13th century, but also researched alchemy, long before true "scientific" methods were established -- would you count arsenic as being discovered by a scientist?  It's kind of a gray area.
67099
In Japan a few years ago the workers at one facility were carrying radioactive solutions in buckets from one place to another where they put so much of it that it started having nuclear reactions from reaching a critical amount.  This was amazing news, but it happens that the people doing mundane, dirty, or high exposure work often know little and are only following or misfollowing instructions of more knowledgeable scientists who are not always there to prevent mistakes.\n\nAlso, one time in the USA, out west, a man was working on a reactor and, they say, everyone had been told not to remove a certain vital control rod.  But he did, and instantly the reactor exploded, releasing radioactive contaminants inside the containment.  The mans body was found on the ceiling impaled by the control rod.\n\nThat sounds like a made up story, I know, but I have heard it told about three times from VERY reputable and different sources.\n\nAnother time was during the testing of fissionable materials in the laboratory at Los Alamos where the first atom bombs were developed.\n\nOne scientist was investigating critical mass by bringing two hemispheres or pieces of fissionable materials slowly closer to each other on some kind of track.  He got them too close and did not get them apart fast enough.  The radiation exposure was so intense he died shortly after that, also I believe one other person who was in the room.
1027730
Oxygen was first discovered by Michał Sędziwój, a Polish alchemist and philosopher in the late 16th century. Sędziwój assumed the existence of oxygen by warming nitre (saltpeter). He thought of the gas given off as "the elixir of life".\nOxygen was again discovered by the Swedish pharmacist Carl Wilhelm Scheele sometime before 1773, but the discovery was not published until after the independent discovery by Joseph Priestley on August 1, 1774, who called the gas dephlogisticated air (see phlogiston theory). Priestley published his discoveries in 1775 and Scheele in 1777; consequently Priestley is usually given the credit. It was named by Antoine Laurent Lavoisier after Priestley's publication in 1775.
144124
One common element that is found on this planet is Carbon. So they study the Half-Life of Radioactive isotopes to comeup with the age of a thing. Before the radioactivity method was discovered, scientists used early method. There is a formula that scientists used (Before the discovery of radioactivity method), which was first derived by Kelvin.\nHere is the formula. \n"\nAge = (To - T)2/ ( pi*K*GG2), \n\nwhere To is the formation temperature, T is today's temperature, pi is 3.14, K is a material property called thermal diffusivity (we'll use 1mm2/sec) and GG is the Earth's geothermal gradient (25 C/km). If To ranges from 1500 to 2000 C, the age of the earth would range from 36-65 m.y." - Courtesy: http://www.globalchange.umich.edu/ \n\nOfcourse, after discovering Radiogenic age determining methods, the way of measuring Age of things has changed.\nHere is the link that has more information of Radiogenic dating methods.\nhttp://www.globalchange.umich.edu/globalchange1/current/lectures/clocks_in_rocks/clocks_in_rocks.html\n\nhttp://www.ucmp.berkeley.edu/fosrec/McKinney.html
756851
Polonium:\n\npo·lo·ni·um (pə-lō'nē-əm) pronunciation\nn. (Symbol Po)\n\nA naturally radioactive metallic element, occurring in minute quantities as a product of radium disintegration and produced by bombarding bismuth or lead with neutrons. It has 27 isotopes ranging in mass number from 192 to 218, of which Po 210, with a half-life of 138.39 days, is the most readily available. Atomic number 84; melting point 254°C; boiling point 962°C; specific gravity 9.32; valence 2, 4.\n\n[From Medieval Latin Polōnia, Poland (the native country of Pierre and Marie Curie, the element's discoverers).]\nPolonium\n\nA chemical element, Po, atomic number 84. Marie Curie discovered the radioisotope 210Po in pitchblende. This isotope is the penultimate member of the radium decay series. All polonium isotopes are radioactive, and all are shortlived except the three ?-emitters, artificially produced 208Po (2.9 years) and 209Po (100 years), and natural 210Po (138.4 days). See also Periodic table.\n\nPolonium (210Po) is used mainly for the production of neutron sources. It can also be used in static eliminators and, when incorporated in the electrode alloy of spark plugs, is said to improve the cold-starting properties of internal combustion engines.\n\nMost of the chemistry of polonium has been determined using 210Po, 1 curie of which weighs 222.2 micrograms; work with weighable amounts is hazardous, requiring special techniques. Polonium is more metallic than its lower homolog, tellurium. The metal is chemically similar to tellurium, forming the bright red compounds SPoO3 and SePoO3. The metal is soft, and its physical properties resemble those of thallium, lead, and bismuth. Valences of 2 and 4 are well established; there is some evidence of hexavalency. Polonium is positioned between silver and tellurium in the electrochemical series.\n\nTwo forms of the dioxide are known: low-temperature, yellow, face-centered cubic (UO2 type), and high-temperature, red, tetragonal. The halides are covalent, volatile compounds, resembling their tellurium analogs.polonium (pəlō'nēəm) , radioactive chemical element; symbol Po; at. no. 84; mass no. of most stable isotope 209; m.p. 254°C; b.p. 962°C; sp. gr. about 9.4; valence +2 or +4. Polonium is an extremely rare element found in uranium ores (about 0.1 gram per ton). A product of radium decay, it is sometimes called radium F. In its physical and chemical properties it resembles tellurium (the element above it in Group 16 of the periodic table) and bismuth. Polonium has 34 isotopes, more than any other element. All of these isotopes are radioactive. The most stable, polonium-209, has a half-life of about 103 years. Polonium-208 (half-life about 3 years) is the only other polonium isotope with a half-life over one year. Although these two isotopes can be prepared in small quantities in a particle accelerator, they are very expensive to produce. All other polonium isotopes are short-lived except polonium-210 (half-life about 138 days), which is the most commonly used isotope. It is prepared by bombarding bismuth with neutrons in a nuclear reactor. It is a highly radioactive material. A milligram of polonium-210 emits as much alpha radiation as about 5 grams of radium, and enough gamma radiation to cause a blue glow in the air around it. It can be used as a heat source, since most of the energy of the alpha radiation is absorbed as heat within the polonium and its container. Polonium has found use in small portable radiation sources and in the control of static electricity. However, it is an extremely toxic substance and must be handled with great care. Polonium was the first element to be discovered because of its radioactivity; it was discovered in pitchblende in 1898 by Marie Curie and named for her native country, Poland.A naturally radioactive metallic element, occurring in minute quantities in uranium ores; its most readily available isotope is Po 210, with a half-life of 138.39 day
796792
Thallium (Greek θαλλός, thallos, meaning "a green shoot or twig") was discovered by Sir William Crookes in 1861 in England while he was making spectroscopic determinations for tellurium on residues from a sulfuric acid plant. The name comes from Thallium's bright green spectral emission lines. In 1862 Crookes and Claude-Auguste Lamy isolated the metal independently of each other.
877460
Mendeleev is best known for his work on the periodic table\n\nhttp://www.chemistry.co.nz/mendeleev.htm
644486
This might help\n\nhttp://216.109.125.130/search/cache?p=how+was+tantalum+discovered&sp=1&ei=UTF-8&fr=FP-tab-web-t&SpellState=n-3467474897_q-gL5DN60DdgiG3lMcas4afwABAA%40%40&u=www.scescape.net/%7Ewoods/elements/tantalum.html&w=tantalum+discovered&d=PMQ_k0aqMkbj&icp=1&.intl=us
123105
"We are in an age of discovery, we live in the world of the uknown. That's the only place to live." —Lloyd Quarterman(1918-1982)\n\n\nDr. Lloyd Quarterman was one of the African American nuclear scientists involved in the production of the atomic bomb. He worked with two of the most illustrious scientific minds of the 20th century—Einstein and Fermi."
581234
In 1938, two German physicists, Otto Hahn and Fritz Straussman, discovered that a neutron caused the nucleus of a uranium atom to split (fission). Other experiments followed that showed that the energy released in fission was about 100 million times greater than a chemical reaction. At the onset of World War II, the military implications of this discovery were readily apparent to leaders of the major powers. Uranium was destined to find new, more important applications beyond its original use as a colorant for glass and ceramics.
887068
Element 118 may have been found about two weeks ago:\n\nhttp://www.fogcityjournal.com/news_in_brief/bcn_livermore_labs_element_118_061016.shtml
74991
Marie Curie discovered Radium and polonium.She deduced that there were other substances besides uranium that were very radioactive, such as polonium and radium, which she discovered in 1898. Raduim was used to cure tumors in cancer patients and the process to using radium to cure malign tumors is called Curietherapy .