Period 6 Element - Atomic Characteristics

Atomic Characteristics

Chemical element			Chemical series	Electron configuration
55	Cs	Caesium	Alkali metal	6s1
56	Ba	Barium	Alkaline earth metal	6s2
57	La	Lanthanum	Lanthanide	5d1 6s2
58	Ce	Cerium	Lanthanide	4f1 5d1 6s2
59	Pr	Praseodymium	Lanthanide	4f3 6s2
60	Nd	Neodymium	Lanthanide	4f4 6s2
61	Pm	Promethium	Lanthanide	4f5 6s2
62	Sm	Samarium	Lanthanide	4f6 6s2
63	Eu	Europium	Lanthanide	4f7 6s2
64	Gd	Gadolinium	Lanthanide	4f7 5d1 6s2
65	Tb	Terbium	Lanthanide	4f9 6s2
66	Dy	Dysprosium	Lanthanide	4f10 6s2
67	Ho	Holmium	Lanthanide	4f11 6s2
68	Er	Erbium	Lanthanide	4f12 6s2
69	Tm	Thulium	Lanthanide	4f13 6s2
70	Yb	Ytterbium	Lanthanide	4f14 6s2
71	Lu	Lutetium	Lanthanide	4f14 5d1 6s2
72	Hf	Hafnium	Transition metal	4f14 5d2 6s2
73	Ta	Tantalum	Transition metal	4f14 5d3 6s2
74	W	Tungsten	Transition metal	4f14 5d4 6s2
75	Re	Rhenium	Transition metal	4f14 5d5 6s2
76	Os	Osmium	Transition metal	4f14 5d6 6s2
77	Ir	Iridium	Transition metal	4f14 5d7 6s2
78	Pt	Platinum	Transition metal	4f14 5d9 6s1
79	Au	Gold	Transition metal	4f14 5d10 6s1
80	Hg	Mercury	Transition metal	4f14 5d10 6s2
81	Tl	Thallium	Post-transition metal	4f14 5d10 6s2 6p1
82	Pb	Lead	Post-transition metal	4f14 5d10 6s2 6p2
83	Bi	Bismuth	Post-transition metal	4f14 5d10 6s2 6p3
84	Po	Polonium	Post-transition metal	4f14 5d10 6s2 6p4
85	At	Astatine	Halogen	4f14 5d10 6s2 6p5
86	Rn	Radon	Noble gas	4f14 5d10 6s2 6p6

• a Note that lutetium (or, alternatively, lanthanum) is considered to be a transition metal, but marked as a lanthanide, as it is considered so by IUPAC.
• b An exception to the Aufbau principle.