Search results
Results From The WOW.Com Content Network
Tantalum is a chemical element; it has symbol Ta and atomic number 73. It is named after Tantalus , a figure in Greek mythology. [ 11 ] Tantalum is a very hard, ductile , lustrous , blue-gray transition metal that is highly corrosion-resistant.
Actinium is a chemical element; it has symbol Ac and atomic number 89. It was first isolated by Friedrich Oskar Giesel in 1902, who gave it the name emanium; the element got its name by being wrongly identified with a substance André-Louis Debierne found in 1899 and called actinium.
First, neptunium-238 (half-life 2.1 days) was synthesized, which then beta-decayed to form the new element with atomic number 94 and atomic weight 238 (half-life 88 years). Since uranium had been named after the planet Uranus and neptunium after the planet Neptune, element 94 was named after Pluto, which at the time was also considered a planet ...
A classical element referred to as the Fifth Element in ancient and medieval times. It is believed to be the material that fills the region of the universe beyond the terrestrial sphere. This belief goes as far back as Plato's Timaeus, where it is said that "there is the most translucent kind which is called by the name of aether (αἰθήρ ...
Heavy metals is a controversial and ambiguous term [2] for metallic elements with relatively high densities, atomic weights, or atomic numbers.The criteria used, and whether metalloids are included, vary depending on the author and context and has been argued should not be used.
[note 2] However, the name "neptunium" had already been given to another proposed chemical element (though not the element that today bears the name neptunium, which was discovered in 1940). [ note 3 ] So instead, Winkler named the new element germanium (from the Latin word, Germania , for Germany) in honor of his homeland. [ 15 ]
It is an extremely radioactive synthetic element (an element not found in nature, but can be created in a laboratory). The most stable known isotope, meitnerium-278, has a half-life of 4.5 seconds, although the unconfirmed meitnerium-282 may have a longer half-life of 67 seconds.
Yttrium is a chemical element; it has symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". [8] Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals and is never found in nature as a free ...