A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides.
These are:
Group
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
#
Name55
Cs56
Ba57-71
72
Hf73
Ta74
W75
Re76
Os77
Ir78
Pt79
Au80
Hg81
Tl82
Pb83
Bi84
Po85
At86
Rn
Lanthanides
57
La58
Ce59
Pr60
Nd61
Pm62
Sm63
Eu64
Gd65
Tb66
Dy67
Ho68
Er69
Tm70
Yb71
Lu
e--conf.
Alkali metals Alkaline earths Lanthanide Actinides Transition metals Other metals Metalloids Nonmetals Halogens Noble gases