A more reactive source of nucleophilic carbon than a Grignard reagent is the alkylated or arylated form of this element, and this element is currently under inspection as a potential generator of tritium in the commercialization of d-t fusion. It is the heaviest stable element to form during Big Bang nucleosynthesis. Older stars are poor in this element while younger ones are unexpectedly rich in 
A more reactive source of nucleophilic carbon than a Grignard reagent is the alkylated or arylated form of this element, and this element is currently under inspection as a potential generator of tritium in the commercialization of d-t fusion. It is the heaviest stable element to form during Big Bang nucleosynthesis. Older stars are poor in this element while younger ones are unexpectedly rich in it. The deuteride of its isotope with mass number 6 is sometimes used as fuel for thermonuclear weapons, and the monovalent ion of this element is used to treat bipolar disorder. For 10 points, name this element which is the first of the alkali metals and has atomic number 3.
A more reactive source of nucleophilic carbon than a Grignard reagent is the alkylated or arylated form of this element, and this element is currently under inspection as a potential generator of tritium in the commercialization of d-t fusion.
lithium