Keychain. Lithium.

<div>   </div> <div> <strong> Atomic number     <span class = "Apple-tab-span" style = "white-space: pre;"> </span> 3 </ strong> </div> <div> <strong> Atomic mass <span class = "Apple-tab-span" style = "white-space: pre;"> </span>     6,941 </strong> </div> <div> <strong> Density, kg / m? <Span class = "Apple-tab-span" style = "white-space: pre;"> </span>   530 </strong> </div> <div> <strong> Temperature </strong></div> <div> <strong> melting, ° С <span class = "Apple-tab-span" style = "white- space: pre; "> </span>       180.5 </strong> </div> <div>   </div> <div> Lithium is a soft, silvery white alkali metal. Lithium was discovered in 1817 by the Swedish chemist and mineralogist Johann Arfvedson, first in the mineral petalite. Lithium metal was first received by Humphrey Davy in 1818. </div> <div> Lithium got its name because it was found in "stones". Originally called "lithion", the modern name was suggested by Berzelius. </div> <div>   </div>