Thulium

LANTHANOID · GROUP None · PERIOD 6

Thulium

168.93

Atomic Data

[Xe] 4f¹³ 6s²

Shell	n	Subshell	Electrons	Cumulative
K	1	1s	2	2
L	2	2s	2	4
L	2	2p	6	10
M	3	3s	2	12
M	3	3p	6	18
M	3	3d	10	28
N	4	4s	2	30
N	4	4p	6	36
N	4	4d	10	46
N	4	4f	13	59
O	5	5s	2	61
O	5	5p	6	67
P	6	6s	2	69
Total			69	69

Thulium is monoisotopic — ¹⁶⁹Tm is its only naturally occurring stable isotope, accounting for 100% of all natural Thulium.

Isotope	Symbol	Protons	Neutrons	Abundance	Stability
Thulium-169	¹⁶⁹Tm	69	100	100	Stable

Thulium is present in Earth's crust at approximately 0.52 ppm by mass and at approximately 0.01 ppm by mass throughout the universe.

Thulium

0.52 ppm

Silicon (ref.)

277,000 ppm

Oxygen (ref.)

461,000 ppm

Thulium

0.01 ppm

Helium (ref.)

230,000 ppm

Hydrogen (ref.)

739,000 ppm

Free periodic table reference sheets for classrooms, study sessions, and laboratory use.

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