Period 6 element
A period 6 element is an element in the sixth period (row) of the periodic table. It contains 32 elements, beginning at Caesium and ending with Radon. The Lanthanides (also called the rare earth elements) are part of this period. The lanthanides stretch from lanthanum (57) to lutetium (71).
Period 6 elements have electrons in the first six electron shells. All period 6 elements have one or more electrons in the sixth electron shell (valence electrons). When atomic number increases by one, another electron is added. Two electrons join the 6s orbital, 14 electrons join the 4f orbital, ten electrons join the 5d orbital, and six electrons join the 6p orbitals.