Dubnium (symbol Db, atomic number 105) is a synthetic superheavy element named after the Dubna research city. It is classified as a transition metal and sits in group 5, period 7 of the periodic table.
Overview
Dubnium is the chemical element with atomic number 105 and the symbol Db. With a standard atomic weight of [268], it is a transition metal. In the periodic table it occupies group 5 and period 7, and under standard conditions it is normally a solid. Dubnium is a synthetic superheavy element named after the Dubna research city.
Atomic structure
An atom of Dubnium has 105 protons in its nucleus and, when neutral, 105 electrons arranged in the configuration [Rn] 5f14 6d3 7s2. Dubnium has no stable isotope; the value [268] refers to the mass number of its most stable or most commonly produced isotope.
Discovery and place in the table
Dubnium was discovered in 1967 by Joint Institute for Nuclear Research. It follows Rutherfordium (Rf) and precedes Seaborgium (Sg) in order of atomic number.
| Atomic number | 105 |
|---|---|
| Symbol | Db |
| Atomic mass | [268] |
| Category | Transition metal |
| Group | 5 |
| Period | 7 |
| Electron configuration | [Rn] 5f14 6d3 7s2 |
| Phase at STP | Solid |
| Discovered | 1967 (Joint Institute for Nuclear Research) |