The electron shell of unquadnilium
Chemical properties
Name, symbol, number: unquadnilium, Uqn, 140
Element category: Superactinide
Group, period, block: N/A, 8, f
Standard atomic weight: [372][1]
Electron configuration: [Uuo] 5g186f27p68s2


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

Unquadnilium, also known as eka-thorium or element 140, is the temporary name of a hypothetical superheavy chemical element in the periodic table in the superactinide series that has the temporary symbol Uqn and has the atomic number 140. 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, unquadnilium 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]


Unquadnilium is a temporary IUPAC systematic element name derived from the digits 140. Research scientists usually refer to the element simply as element 140.


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