- The heaviest known element, oganesson, shows very unusual physical and chemical properties.
- Oganesson is the first noble gas that is surprisingly chemically reactive.
- Unlike other noble gas, electrons in oganesson are assembled in a nebulous blob, rather than in discrete shells.
Do you know there have been more than 700 types of element tables till date, with new atoms being added frequently, filling void blocks in the table.
The most recent entry in the noble gas column is oganesson (Og) – the element with highest known atomic number (118). First synthesized in 2002, it’s the first superheavy noble gas atom.
Because of low production rate and short half-life (about 1 millisecond), oganesson is very difficult to study. Scientists need to rely on atomic measurements to establish the basic properties of this element. They’ve carefully studied the element and discovered that its physical and chemical properties are very different from other noble gas atoms.
The advanced simulation suggests that oganesson is even weirder than previously thought. It is different in many ways, and this could provide us some fundamental insights of how such superheavy elements work. Below, we’ve tried to explain some of the unusual properties and nature of the oganesson.
Scientists used fermion localization, a technique for visualizing nucleon or electron spatial distribution, to specify the structure within the element. What they found is, both nucleons and electrons have a uniform distribution, in utter contrast to the nonuniform shell structure of less-heavy atoms.
Like radon and xenon, electrons in oganesson must be arranged in shells around the nucleus. But things are quite different here, rather than simply residing in discrete shells, electrons in oganesson appears to be a nebulous blob. This strange behavior is explained by the special theory of relativity by Einstein that considers fast-moving electrons in superheavy atoms.
Simulations | Credit: Physics Review Letters
As you can see in the image, the top row shows that electrons exist in different shells (green). The bottom row considers the theory of relativity, suggesting that electrons in oganesson are organized in a nebulous blob, unlike xenon and radon.
Reference: Physcial Review Letters | doi:10.1103/PhysRevLett.120.053001
A Noble Gas That’s Reactive
The simulations suggest that protons, electrons and neutrons in the oganesson don’t follow the noble-gas-rule. It’s grouped with other noble gases that do not react with any other atoms. However, because of different electron configuration, oganesson it the only noble gas that is capable of receiving and giving away its electrons. This makes the element chemically reactive.
Gas With Solid-State Property
Image credit: P. Jerabek and Alan Stonebraker
The unique configuration of electrons in oganesson could let the atoms stick together, rather than just bouncing off one another (like gas). Unlike other noble gases, atoms of oganesson could assemble together in a solid, at room temperature.
A study presented preliminary measurements for the rare gas solids up to the heaviest element Oganesson. The cohesive energy of nearly 500 meV for Oganesson was measured to be unexpectedly high when compared to the other rare gas solids that’s most likely caused by the strong spin-orbit. This lead to an increased dipole polarizability for Oganesson (59 au), compared to Radon (33.2 au).
Usually, protons inside the atom’s nucleus repel each other because of their same (positive) charges, but strong nuclear force makes them stay bounded. In oganesson, however, the number of protons is very large, which could together overcome the nuclear force, forming a bubble with few protons at the center of the nucleus. In fact, some studies discovered a “bubble nucleus” in unstable version of silicon.
Unlike protons in oganesson’s nucleus that are expected to be in different shells, the neutrons in the element are supposed to be combined. The is quite odd as compared to other heavy elements where neutron rings are well-established.
These crucial insights about oganesson’s nature open the possibilities to further theoretically examine its bizarre properties. The significant results could encourage other researchers and experimentalists to build instruments and tools to enable further studies of superheavy elements.