1 +Gallium is a silvery-white transition metal with a melting point of only 30 degrees Celsius, just above room temperature. It is mainly produced as a by-product of Aluminum. The creator of the periodic table, Dmitri Mendeleev, left 4 empty spaces because he assumed that there would be elements there. He was right, and Gallium was the first of these 4 missing elements to be found. It has some properties similar to semiconductors. It has oxidation states of +3 and +1 with +3 being the most prevalent. It was discovered in 1875 by the French chemist  Paul-Emile Lecoq de Boisbaudran.

Gallium finds many uses. It is used as an alternative to Mercury in some thermometers because it is less toxic. It is also used as a semiconductor in the form of Gallium Arsenide. It is used in alloys to soften them and lower their melting point. It also has a few uses in the medical industry as well in medicine, and locating tumors.