It is a highly radioactive metallic element that is similar to selenium and tellurium, chemically. None are stable. Polonium-210 is the most readily available. Polonium (84 Po) has 42 isotopes, all of which are radioactive, with between 186 and 227 nucleons. First identified in 1898, and also marking the discovery of the element polonium, 210 Po is generated in the decay chain of uranium-238 and radium-226. Twenty five isotopes of polonium are known, with atomic masses ranging from 194 to 218. This is a list of chemical elements, sorted by atomic mass (or most stable isotope) and color coded according to type of element.Each element's atomic number, name, element symbol, and group and period numbers on the periodic table are given. Isotopes: Polonium has 29 isotopes whose half-lives are known, with mass numbers 190 to 218. Polonium Element in Periodic Table | Atomic Number Atomic Mass. None are stable. Element Polonium (Po), Group 16, Atomic Number 84, p-block, Mass [209]. The highly radioactive isotope of Polonium (Po-210) is … The chemical symbol for Hydrogen is H.. With a standard atomic weight of circa 1.008, hydrogen is the lightest element on the periodic table. Polonium, a radioactive, silvery-gray or black metallic element of the oxygen group (Group 16 [VIa] in the periodic table). Weights of atoms and isotopes are from NIST article. The most stable isotope is 209 Po, with a half-life of 102 years. Its atomic number 84 and its symbol is Po. 210 Po with a half-life of 138.376 days has the longest half-life of naturally occurring polonium. Isotopes of mass 209 (half-life 103 years) and mass 208 (half-life 2.9 years) can be prepared by alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron, but these are expensive to produce. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass. The first element to be discovered by radiochemical analysis, polonium was discovered in 1898 by Pierre and Marie Curie, who were investigating the radioactivity of a certain pitchblende. Name: Polonium Symbol: Po Atomic Number: 84 Atomic Mass: (209.0) amu Number of Protons/Electrons: 84 Number of Neutrons: 125 Date of Discovery: 1898 Discoverer: Pierre and Marie Curie Uses: No uses known Classification: Metalloid 418 reads; Polonium Element: Polonium Element-Polonium is a chemical element in the p-block, 16 th group and 6 th period of periodic table. 209 Po and 208 Po (half-life 2.9 years) can be made through proton bombardment of bismuth in a cyclotron. Initiators made of polonium-210 and beryllium were located at the center of the fissile cores of early atomic weapons. Molecular mass (molecular weight) is the mass of one molecule of a substance and is expressed in the unified atomic mass units (u). Name: Polonium: Symbol: Po: Atomic Number: 84: Atomic Mass: 209 atomic mass units: Number of Protons: 84: Number of Neutrons: 125: Number of Electrons: 84: Melting Point Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images. 209 Po, with a half-life of 125 years, has the longest half-life of all isotopes of polonium. Polonium-210 (210 Po, Po-210, historically radium F) is an isotope of polonium.It undergoes alpha decay to stable 206 Pb with a half-life of 138.376 days, the longest of all naturally occurring polonium isotopes. (1 u is equal to 1/12 the mass of one atom of carbon-12) Molar mass (molar weight) is the mass of one mole of a substance and is expressed in g/mol. Hydrogen is a chemical element with atomic number 1 which means there are 1 protons and 1 electrons in the atomic structure. Substance in the Universe, constituting roughly 75 % of all baryonic Mass from... 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