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 out after ... Estimates suggest that there is only about 30 g of francium in the whole of the Earth's crust.

Mrs Roberts: So, the chemical symbol is Al. See if you can see it in the periodic table. Cal: OK. It is. It's on the right hand side. It's right there. Magic. OK, well I might have been able to ...