Dubnium

Transition metal · atomic number 105

105268DbDubniumSolidTransition metal

Dubnium is a chemical element with symbol Db and atomic number 105. It is named after the town of Dubna in Russia (north of Moscow), where it was first produced. It is a synthetic element (an element that can be created in a laboratory but is not found in nature) and radioactive; the most stable known isotope, dubnium-268, has a half-life of approximately 28 hours.

Properties of Dubnium

Element category	Transition metal
Atomic number	105
Atomic mass	268 u
Phase at STP	Solid
Group	5
Period	7
Block	d
Electron configuration	*[Rn] 5f14 6d3 7s2
Electrons per shell	2, 8, 18, 32, 32, 11, 2
Density	29.3 g/cm3
Discovered by	Joint Institute for Nuclear Research

← Rutherfordium · Periodic table · Seaborgium → Sg

About the transition metal group

The dense, strong, catalytic heart of the table — iron, copper, gold, titanium — responsible for most of metallurgy, jewellery and industry.

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11 elements: Elements that readily gain or share electrons — the building blocks of water, air, living tissue and most organic chemistry.

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6 elements: Full outer electron shells make these gases almost inert: they barely react, glow in discharge lamps and are used to create unreactive atmospheres.

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35 elements: The dense, strong, catalytic heart of the table — iron, copper, gold, titanium — responsible for most of metallurgy, jewellery and industry.

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8 elements: Superheavy synthetic elements made atom-by-atom, existing for fractions of a second; their true chemistry is still unmeasured.