Thulium

Atomic Number: 69
Symbol: Tm
Atomic Mass: 168.93 u
Number of Neutrons: 100
Melting Point: 1545°C
Boiling Point: 1730°C
Electrons per shell: 2.8.18.31.8.2
Electron configuration: [Xe] 4f¹³ 6s²

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Thulium is the 69th element in the periodic table and it is part of the lanthanide series. It has a bright silvery-gray color and is soft enough to be cut though by a knife. It slowly breaks apart in air, but is more resistant to this than most other rare-earth elements. It is one of the least abundant elements from the rare-earth elements group. This element is considered to be non-toxic. Thulium is not found freely in nature but is found in ores and minerals. There are 2 ores which thulium can be found in, monazite, which contains about 0.007% of thulium, and bastnasite which contains about 0.0008%. These ores can be mined in China, US, Brazil, India, Sri lanka and Australia. Thulium was discovered by Per Teodor Cleve, a Swedish chemist, in 1879.

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