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Carl Wilhelm Scheele (German:, Swedish: [ˈɧêːlɛ]; 9 December 1742 – 21 May 1786 [2]) was a German Swedish [3] pharmaceutical chemist.. Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified molybdenum, tungsten, barium, nitrogen, and chlorine, among others.
Barium found in the Earth's crust is a mixture of seven primordial nuclides, barium-130, 132, and 134 through 138. [15] Barium-130 undergoes very slow radioactive decay to xenon-130 by double beta plus decay, with a half-life of (0.5–2.7)×10 21 years (about 10 11 times the age of the universe).
This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×10 21 years (about 10 11 times the age of the universe). There are a total of thirty-three known radioisotopes in addition to 130 Ba.
The Group 1 metal (M) is oxidised to its metal ions, and water is reduced to hydrogen gas (H 2) and hydroxide ion (OH −), giving a general equation of: 2 M(s) + 2 H 2 O(l) 2 M + (aq) + 2 OH − (aq) + H 2 (g) [8] The Group 1 metals or alkali metals become more reactive as their number of energy levels inceases.
Metallic ions in aqueous solution display many colours: • the red cobalt cation Co 2+ from Co(NO 3) 2 (see § Co) • the orange chromium oxyanion Cr 2 O 2− 7 from K 2 Cr 2 O 7 • the yellow chromium oxyanion CrO 2− 4 from K 2 CrO 4 • the turquoise nickel cation Ni 2+ from NiCl 2
By 1829, Döbereiner had found other groups of three elements (hence "triads") whose physical properties were similarly related. [2] He also noted that some quantifiable properties of elements (e.g. atomic weight and density) in a triad followed a trend whereby the value of the middle element in the triad would be exactly or nearly predicted by taking the arithmetic mean of values for that ...
Y-type ferrite has a chemical formula of Me L 2 Me S 14 O 22 with a space group of ¯. One example is Ba 2 Co 2 Fe 12 O 22 with a = 5.86 Å and c = 43.5 Å. [9] Y-type ferrite is built up with S and T blocks with an order of 3(ST) in one unit cell. There is no horizontal mirror plane in a Y-type ferrite.
A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the chemical elements, including the lanthanides.The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements ...