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Selenium (34 Se) has six natural isotopes that occur in significant quantities, along with the trace isotope 79 Se, which occurs in minute quantities in uranium ores. Five of these isotopes are stable: 74 Se, 76 Se, 77 Se, 78 Se, and 80 Se. The last three also occur as fission products, along with 79 Se, which has a half-life of 327,000 years ...
Selenium is a chemical element; it has the symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust.
The chalcogens (ore forming) (/ ˈkælkədʒənz / KAL-kə-jənz) are the chemical elements in group 16 of the periodic table. [1] This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive elements polonium (Po) and livermorium (Lv). [2]
Selenium-79 is a radioisotope of selenium present in spent nuclear fuel and the wastes resulting from reprocessing this fuel. It is one of only seven long-lived fission products. Its fission yield is low (about 0.04%), as it is near the lower end of the mass range for fission products. Its half-life has been variously reported as 650,000 years ...
Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number; [5] siderophiles shown in yellow. Graphs of abundance against atomic number can reveal patterns relating abundance to stellar nucleosynthesis and geochemistry. The alternation of abundance between even and odd atomic number is ...
Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in its native form as elemental crystals.
The most abundant isotopes -Isotopes with equal numbers of protons and neutrons are unusually abundant. Relative abundance is proportional to the area. (large blue circle) comprises 74% of the ordinary matter of the universe. Color corresponds to nucleosynthetic process: Blue: Big Bang; Green: dying low-mass stars; Yellow: exploding massive stars.
A metalloid is a chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals. The word metalloid comes from the Latin metallum ("metal") and the Greek oeides ("resembling in form or appearance"). [1] There is no standard definition of a metalloid and no complete agreement on which ...