Rubidium has one valence electron, which is located in the s-orbital of the atom's fifth energy level. Rubidium has a total of 37 electrons, illustrated in the element's electron configuration of 1s2 2s2p6 3s2p6d10 4s2p6 5s1.
Rubidium is represented by the chemical symbol Rb on the periodic table of elements. Its atomic number is 37, and it is part of a group of elements known as alkali metals. An atom of rubidium has an ionic radius of 1.52 angstroms and an atomic radius of 2.98 angstroms. In its most common state, rubidium has 48 neutrons, while in an ionic state it has a charge of +1.