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In total, barium has 40 known isotopes, ranging in mass between 114 and 153. The most stable artificial radioisotope is barium-133 with a half-life of approximately 10.51 years. Five other isotopes have half-lives longer than a day. [16] Barium also has 10 meta states, of which barium-133m1 is the most stable with a half-life of about 39 hours ...
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 longest-lived of these is 133 Ba, which has a half-life of 10.51 years ...
Barium is used in vacuum tubes as a getter to remove gases. [61] Barium sulfate has many uses in the petroleum industry, [4] [81] and other industries. [4] [61] [82] Radium has many former applications based on its radioactivity, but its use is no longer common because of the adverse health effects and long half-life.
Here [Ne] refers to the core electrons which are the same as for the element neon (Ne), the last noble gas before phosphorus in the periodic table. The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below.
No known element has more than 32 electrons in any one shell. [25] [26] This is because the subshells are filled according to the Aufbau principle. The first elements to have more than 32 electrons in one shell would belong to the g-block of period 8 of the periodic table. These elements would have some electrons in their 5g subshell and thus ...
This tendency is called the 18-electron rule, because each bonded atom has 18 valence electrons including shared electrons. The heavy group 2 elements calcium, strontium, and barium can use the (n−1)d subshell as well, giving them some similarities to transition metals. [7] [8] [9]
The 4s and 3d subshells have approximately the same energy and they compete for filling the electrons, and so the occupation is not quite consistently filling the 3d orbitals one at a time. The precise energy ordering of 3d and 4s changes along the row, and also changes depending on how many electrons are removed from the atom.
A thorium atom has 90 electrons, ... barium, thallium, and ... so that it does not have a chance to capture a neutron and will only decay to 233 U. ...