What is Period 5 element?
A '''period 5 element''' is an [[Chemical element|element]] in the fifth [[period (periodic table)|period]] (row) of the [[periodic table]]. It contains 18 elements, beginning at [[Rubidium]] and ending at [[Xenon]]. Period 5 elements have [[electrons]] in the first five [[electron shell]]s. All period 5 elements have one or more electrons in the fifth electron shell ([[valence electrons]]). When atomic number increases by one, another electron is added. Two electrons join the 5s [[atomic orbital|orbital]], ten electrons join the 4d orbital, and six electrons join the 5p orbitals. {{Periodic tables footer}} [[Category:Periodic table]] {{chem-stub}}