All practice pages/Interatomic theory/Elements
Element 105, a transition metal
Named after Dubna, the Russian research town where many of the heaviest elements were first made.
Period 7, group 5. The other transition metals are tinted, and every cell opens its own article.
Dubnium has 105 electrons, one for every proton, so the atom carries no charge. Below are the same 105 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d³ 7s²
Short form: [Rn] 5f¹⁴ 6d³ 7s², where [Rn] stands for the 86 electrons radon already has.
That list runs by shell. In the order the subshells fill it reads [Rn] 7s² 5f¹⁴ 6d³, because a subshell fills by its energy, not by its shell number.
The simple form counts electrons shell by shell. The orbital form says which subshell each one sits in: s holds 2, p holds 6, d holds 10 and f holds 14. Shell 4 here is 4s² 4p⁶ 4d¹⁰ 4f¹⁴, and 2 + 6 + 10 + 14 is 32.
Dubnium sits in period 7 and has 7 shells. The period number counts the shells.
No one has measured this configuration. Only a few atoms of dubnium have ever existed, so it is predicted from the pattern of the table.
The outer shell holds 2 electrons. Those are the ones dubnium can lose, gain or share, so they are the ones that decide what it bonds with.
Only a handful of atoms have ever been made, each lasting seconds or less, so its chemistry is predicted from its place in the table rather than measured.
Not found in nature. It is made a few atoms at a time in particle accelerators by fusing lighter nuclei, and each atom decays within seconds to hours.
Georgy Flerov's team at Dubna reported it in 1968, and Albert Ghiorso's team at Berkeley reported it in 1970 and proposed the name hahnium. IUPAC gave shared credit and in 1997 named it dubnium, after the town that is home to the Joint Institute for Nuclear Research.
Research only. Its longest-lived isotope lasts about a day, a long time for so heavy an element.