This group includes the least electronegative element as well as the lightest and least dense solid metal.
The 87-isotope of one member of this group was used in 1995 to create the first Bose-Einstein Condensate. Another member of this group is used in atomic clocks and its 133-isotope was used in the definition of a second. This group includes the least electronegative element as well as the lightest and least dense solid metal. Rubidium, cesium, and francium are, for 10 points, members of what elemental group composed of metals that all form a plus one charge, whose other members are lithium, sodium and potassium?
The 87-isotope of one member of this group was used in 1995 to create the first Bose-Einstein Condensate.
{Alkali} metals (do not accept alkaline earth metals)