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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. The actinide series, a set of 15 elements between actinium ...
Francium is a chemical element; it has symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223 (originally called actinium K after the natural decay chain in which it appears), has a half-life of only 22 minutes. [ 4 ] It is the second-most electropositive element, behind only caesium, and is the ...
Gold pentafluoride, along with its derivative anion, AuF − 6, and its difluorine complex, gold heptafluoride, is the sole example of gold(V), the highest verified oxidation state. [ 53 ] Some gold compounds exhibit aurophilic bonding , which describes the tendency of gold ions to interact at distances that are too long to be a conventional Au ...
Group 3is the first group of transition metalsin the periodic table. This group is closely related to the rare-earth elements. It contains the four elements scandium(Sc), yttrium(Y), lutetium(Lu), and lawrencium(Lr). The group is also called the scandium groupor scandium familyafter its lightest member. The chemistry of the group 3 elements is ...
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods ") and columns (" groups "). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order ...
edit. Gold (79 Au) has one stable isotope, 197 Au, and 40 radioisotopes, with 195 Au being the most stable with a half-life of 186 days. Gold is currently considered the heaviest monoisotopic element. Bismuth formerly held that distinction until alpha-decay of the 209 Bi isotope was observed. All isotopes of gold are either radioactive or, in ...
Periodic table (crystal structure) For elements that are solid at standard temperature and pressure the first table gives the crystalline structure of the most thermodynamically stable form (s) in those conditions. Each element is shaded by a color representing its respective Bravais lattice, except that all orthorhombic lattices are grouped ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 9 October 2024. Development of the table of chemical elements The American chemist Glenn T. Seaborg —after whom the element seaborgium is named—standing in front of a periodic table, May 19, 1950 Part of a series on the Periodic table Periodic table forms 18-column 32-column Alternative and extended ...