Page 47 - Curriculum Visions Dynamic Book

Dubnium (Db)
Element 105. Formerly known as unnilpentium (Unp), hahnium (Ha) and nielsbohrium (Ns).
It is an artificial radioactive element belonging to the transition metals in the Periodic Table.
Discovery
It was discovered in 1967 at the Joint Institute for Nuclear Research in Dubna, Russia, through experiments involving reactions between americium ions
and neon ions. In 1970 Albert Ghiorso
and others produced dubnium at the University of California at Berkeley.
These researchers reacted californium isotopes with a nitrogen ion and berkelium with a nitrogen ion.
Originally American workers proposed the name hahnium after the late German scientist Otto Hahn, but the International Union of Pure and Applied Chemistry panel members recommended that in 1977 element 105 be renamed dubnium (symbol Db) after the site of the Joint Institute for Nuclear Research in Russia.
Technology
So far, so little of it has been produced that it has no uses, and no one is yet sure of all of its properties.
Geology
It is a synthetic element and so does not occur in the environment.
Biology
Because it is synthetic, it has no role in living things; but since it is radioactive, it is potentially harmful.
Key facts...
Name: Dubnium
Symbol: Db
Atomic number: 105
Atomic weight: 262
Position in Periodic Table: transition metal,
group (5) (vanadium group); period 7 State at room temperature: solid Colour: unknown
Density: n/a
Melting point: n/a
Boiling point: n/a
Origin of name: named after the Joint Institute
for Nuclear Research at Dubna, Russia
Shell pattern of electrons: 2–8–18–32–32–11–2
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