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Scandium is only the 50th most common element on Earth (35th most abundant element in the crust), but it is the 23rd most common element in the Sun [17] and the 26th most abundant element in the stars. [18] However, scandium is distributed sparsely and occurs in trace amounts in many minerals. [19]
The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium ... 4s 2: 2: 8: 8: 2: 21 Sc scandium : ...
Atomic number (Z): 21: Group: group 3: Period: period 4: Block d-block Electron configuration [] 3d 1 4sElectrons per shell: 2, 8, 9, 2: Physical properties; Phase at ...
In chemistry and atomic physics, an electron shell may be thought of as an orbit that electrons follow around an atom's nucleus.The closest shell to the nucleus is called the "1 shell" (also called the "K shell"), followed by the "2 shell" (or "L shell"), then the "3 shell" (or "M shell"), and so on further and further from the nucleus.
Gadolinium isotopes have four metastable isomers, with the most stable being 143m Gd (t 1/2 = 110 seconds), 145m Gd (t 1/2 = 85 seconds) and 141m Gd (t 1/2 = 24.5 seconds). The isotopes with atomic masses lower than the most abundant stable isotope, 158 Gd, primarily decay by electron capture to isotopes of europium .
Scandium concentrates in the liver and is a threat to it; some of its compounds are possibly carcinogenic, even though in general scandium is not toxic. [80] Scandium is known to have reached the food chain, but in trace amounts only; a typical human takes in less than 0.1 micrograms per day. [80]
Since metals can display multiple oxidation numbers, the exact definition of how many "valence electrons" an element should have in elemental form is somewhat arbitrary, but the following table lists the free electron densities given in Ashcroft and Mermin, which were calculated using the formula above based on reasonable assumptions about ...
Electron affinity can be defined in two equivalent ways. First, as the energy that is released by adding an electron to an isolated gaseous atom. The second (reverse) definition is that electron affinity is the energy required to remove an electron from a singly charged gaseous negative ion.