Period 2 element two make up all natural occurrence of lithium on Earth, although further isotopes have been synthesized. In ionic compounds, lithium loses an electron to become positively charged, forming the cation Li. Lithium is the first alkali metal in the periodic table, and the first metal of any kind in the periodic table. At standard temperature and pressure, lithium is a soft, silver-white, highly reactive metal. With a density of 0.564 g·cm, lithium is the lightest metal and the least dense solid element. Lithium is one of the few elements synthesized in the Big Bang, making it a primordial element. Lithium
Dense order a set "X" to be dense are: None of them are necessary. A non-empty and dense relation cannot be antitransitive. A strict partial order < is a dense order iff < is a dense relation. A dense relation that is also transitive is said to be idempotent. Dense order In mathematics, a partial order or total order < on a set "X" is said to be dense if, for all "x" and "y" in "X" for which "x" < "y", there is a "z" in "X" such that "x" < "z" < "y". The rational numbers with the ordinary ordering