primordial is an element or compound which occurs naturally in the earth.
primordial is an element or compound which occurs naturally in the earth.
an element or compound which occurs naturally in the earth is a(n)?
primordial
uranium is a chemical element with the symbol u and atomic number 92. it is a silvery-grey metal in the actinide series of the periodic table. a uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. uranium is weakly radioactive because all isotopes of uranium are unstable, with half-lives varying between 159,200 years and 4.5 billion years. the most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on earth) and uranium-235 (which has 143 neutrons). uranium has the highest atomic weight of the primordially occurring elements. its density is about 70% higher than that of lead, and slightly lower than that of gold or tungsten. it occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.
uranium
4,5-dihydroxy-2,3-pentanedione









































4,5-dihydroxy-2,3-pentanedione (dpd) is an organic compound that occurs naturally but exists as several related structures. the idealized formula for this species is chc(o)c(o)ch(oh)choh, but it is known to exist as several other forms resulting from cyclization. it is not stable at room temperature as a pure material, which has further complicated its analysis. the ("s")-stereoisomer occurs naturally. it is typically hydrated, i.e., one keto group has added water to give the geminal diol.
4,5-dihydroxy-2,3-pentanedione