Francium

Lithium, sodium, potassium, rubidium, caesium and francium are alkali metals.

At any given moment, there are perhaps eight francium atoms in the whole of the earth.

Francium is a chemical element of the symbol Fr.

The atomic number for francium is 87.

The most elusive element of all, however, appears to be francium, which is so rare that it is thought that our entire planet may contain, at any given moment, fewer than twenty francium atoms.

Notice that franciums are balanced without even thinking in moles, atoms, or whatever.

(a) Radons and poloniums are compared, (b) poloniums and astatines are compared and (c) radons and franciums are compared.