The electron shell of untriennium
Chemical properties
Name, symbol, number: untriennium, Ute, 139
Element category: Superactinide
Group, period, block: N/A, 8, f
Standard atomic weight: [370][1]
Electron configuration: [Uuo] 5g186f17p68s2


Phase: Unknown
Density (near r.t.): Unknown
Melting point: Unknown
Boiling point: Unknown
Oxidation states: Unknown
Atomic radius: Unknown
Discoverer None of as yet
Location discovered None of as yet
Date discovered None of as yet

Untriennium, also known as eka-actinium or element 139, is the temporary IUPAC name of a hypothetical superheavy chemical element in the periodic table in the superactinide series that has the temporary symbol Ute and has the atomic number 139. In the periodic table of elements, it is a f-block element. As of 2012, no attempt has been made to synthesize this element.


Currently, untriennium goes under a systematic temporary element name. Since it is very far in the periodic table and has never been synthesized, very little is known about this element. It is also probable that, due to drip instabilities, only the lighter superactinides are physically possible and the periodic table may end soon after the island of stability expected to be centered at element 126.[3]


Untriennium is a temporary IUPAC systematic element name derived from the digits 139. Research scientists usually refer to the element simply as element 139.


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