When Mendeleev first proposed his periodic table in 1869 he left gaps for elements not yet discovered, but that he predicted should exist. One such gap was one beneath caesium, a position later found ...

It was recognized early on that the periodic table more or less fizzles ... As it turns out, francium was one of the last natural elements to be discovered, and is the second rarest after astatine.

Watch this video to find out more information on the periodic table close periodic tableA table which lists all of the chemical elements and arranges them in a way that is useful. It allows us to ...

so it is expected that francium is slightly more electronegative. Electronegativity generally increases as you move from left to right across a period in the periodic table. It decreases as you move ...