Extended periodic table
Elements 157 to 166
The transition metals in period 8 are expected to be elements 157 to 165 (or perhaps with element 121 replacing 157, similarly to the dispute on whether lanthanum or lutetium is better placed as the first 5d transition metal).

Extended periodic table

Section Title: Elements 157 to 166
Table Section Text: The transition metals in period 8 are expected to be elements 157 to 165 (or perhaps with element 121 replacing 157, similarly to the dispute on whether lanthanum or lutetium is better placed as the first 5d transition metal).

Property	156	157	158	159	160	161	162	163	164	165	166

Standard atomic weight	[445]	[448]	[452]	[456]	[459]	[463]	[466]	[470]	[474]	[477]	[481]

Group	Yb group (4)	3 (5)	4 (6)	5 (7)	6 (8)	7 (9)	8 (10)	9 (11)	10 (12, 14, 18)	11 (1, 13)	12 (2, 14)

Valence electron configuration	7d2	7d3	7d4	7d4 9s1	7d5 9s1	7d6 9s1	7d7 9s1	7d8 9s1	7d10	7d10 9s1	7d10 9s2

Stable oxidation states	2	3	4	1, 5	2, 6	3, 7	4, 8	5	0, 2, 4, 6	1, 3	2

First ionization energy	400 kJ/mol	450 kJ/mol	520 kJ/mol	340 kJ/mol	420 kJ/mol	470 kJ/mol	560 kJ/mol	620 kJ/mol	690 kJ/mol	520 kJ/mol	630 kJ/mol

Metallic radius	170 pm	163 pm	157 pm	152 pm	148 pm	148 pm	149 pm	152 pm	158 pm	250 pm	200 pm

Density	26 g/cm3	28 g/cm3	30 g/cm3	33 g/cm3	36 g/cm3	40 g/cm3	45 g/cm3	47 g/cm3	46 g/cm3	7 g/cm3	11 g/cm3

Sentence(s)

The atomic mass of element 156 is 445.

final_sentence: The atomic mass of element 156 is 445.