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
Isotopes of niobium Isotopes of niobium Naturally occurring niobium (Nb), is composed of one stable isotope (Nb). Nb is the lightest nuclide theoretically susceptible to spontaneous fission, and although this has never been observed, it makes niobium theoretically the lightest element with no stable isotope. The first 40 elements (to zirconium) all have at least one stable nuclide susceptible in theory only to proton decay. The most stable radioisotope is Nb with a half-life of 34.7 million years. The next longest-lived niobium nuclides are Nb (half-life: 20,300 years), and Nb with a half-life of 680 years. There is also a meta state at