Chem Explorers

Unraveling the Enigma: Exploring the Rare Element Oganesson

Definition and History

Oganesson is a synthetic element and the heaviest of all elements currently known in the periodic table, with an atomic number of 118. It is a radioactive noble gas that was first synthesized in 2002 by a team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia.

The name oganesson honors the Russian physicist Yuri Oganessian, who played a crucial role in the discovery of several superheavy elements. One of the most intriguing aspects of oganesson is its rarity.

To date, only a few atoms of oganesson have ever been created, and they can only be produced in a laboratory setting by colliding lighter nuclei together at extremely high energies. Furthermore, because of its short half-life, oganesson is incredibly unstable and decays rapidly into other elements.

Position in the Periodic Table

Oganesson is part of the inert gas series and belongs to Group 18 of the periodic table. In terms of its position in the periodic table, oganesson holds the highest atomic number of any element and has the highest atomic mass of all the known elements.

Because of its position in the periodic table, oganesson shares the same characteristics as other noble gases, such as argon, helium, and neon.

Symbol and Group in the Periodic Table

The atomic symbol for oganesson is Og, and it is located in Group 18 of the periodic table, also known as the noble gas group or VIIIA group. Elements in this group are known for their chemical inertness and unreactivity, which is why they are frequently referred to as inert gases.

Oganesson is unique in that it is more reactive than other noble gases and can potentially form compounds with other elements. However, due to its short half-life and the difficulties involved in studying such a rare element, little is known about its chemical properties.

Oganesson Period and Block

In the periodic table, elements are arranged in rows and columns according to their increasing atomic number, electronic configuration, and chemical properties. The rows are known as periods, and they are designated by the numbers 1 to 7, while the columns are known as groups and are designated by the numbers 1 to 18.

Period in the Periodic Table

Oganesson belongs to period 7 of the periodic table, which means that it has seven electron shells surrounding its nucleus. These shells are numbered from 1 to 7, with the first shell closest to the nucleus and the seventh shell furthest away.

In the case of oganesson, the outermost shell or valence shell contains only one electron. The electronic configuration of oganesson is [Rn] 5f14 6d10 7s2 7p6, where [Rn] represents the electron configuration of the noble gas radon, which occupies the previous period.

The valence shell of oganesson is the 7p subshell, which can hold up to six electrons. However, in oganesson, this subshell contains only one electron.

Block in the Periodic Table

The periodic table is also divided into blocks based on the types of subshells that are being filled as one moves across a period. In the case of oganesson, it belongs to the p-block of elements, which includes groups 13 to 18 or columns 13 to 18 in the periodic table.

In the p-block, the valence electrons occupy the p subshells, which are located on the right side of the periodic table. These subshells are filled according to the Aufbau principle, which states that electrons occupy the lowest available energy level or sublevel before filling higher levels.

For oganesson, the p subshell in the seventh period is the 7p subshell, which can hold up to six electrons. However, oganesson has only one electron in its 7p subshell, making it an anomaly in the p-block.

Oganesson Atomic Number, Weight and Electronegativity

Atomic Number and Weight

Oganesson has an atomic number of 118, which means that it has 118 protons in its nucleus. It is the heaviest of all the elements, and its atomic weight is estimated at 294 daltons.

The atomic weight is a measure of the average weight of all the isotopes of an element, taking into account their natural abundance. On the carbon scale, the atomic weight of carbon-12 is defined as 12, and all other elements’ atomic weights are expressed relative to it.

In the case of oganesson, its atomic weight is almost 25 times that of carbon-12, indicating that it is an extremely heavy element.


Electronegativity is a measure of an element’s ability to attract electrons towards itself in a chemical bond. It is usually measured using the Pauling scale, which assigns a value between 0 and 4 to each element, with higher values indicating higher electronegativity.

Oganesson, as an inert gas, has a very low electronegativity value, similar to the other noble gases. The halogen elements, which are located in the same period as oganesson, have the highest electronegativity values in the periodic table.

The electronegativity of oganesson has not been experimentally determined due to its instability and rarity.

Oganesson Atomic Density and Melting/Boiling Point

Atomic Density

The atomic density of an element is defined as its mass per unit volume, and it is expressed in g/cm3. For oganesson, the atomic density is expected to be extremely high due to its very high atomic weight of 294, which is almost 25 times that of carbon-12.

The formula for calculating atomic density is:

Atomic density = (atomic weight / Avogadro’s number) / molar volume

Using this formula, the atomic density of oganesson is estimated to be about 4.9 g/cm3, which is higher than any other element in the periodic table.

Melting/Boiling Point

The melting and boiling points of an element are physical properties that are dependent on a variety of factors, including the element’s atomic structure, molecular weight, and radioactive nature.

In the case of oganesson, its unstable and radioactive nature makes it challenging to determine accurate values for its melting and boiling points. Furthermore, the temperature required to melt or boil an element varies depending on the pressure under which it is being heated.

Based on theoretical calculations and extrapolations, the melting point of oganesson is expected to be around 303 K (30℃), while its boiling point is expected to be around 350 K (77℃).

Oganesson Van der Waals and Ionic Radius

Van der Waals Radius

The Van der Waals radius of an element is defined as the radius of an atom when it is not bonded with any other atom and is interacting through weak, intermolecular forces. This radius takes into account the screening effect of other electrons in the same atom, as well as the nucleus’ attraction for the outermost electron.

Oganesson is an inert gas, which means that it does not form covalent bonds with other elements. As a result, its Van der Waals radius is the most relevant measure of its atomic size.

The Van der Waals radius of oganesson is predicted to be about 152 pm or picometers, which is larger than that of any other noble gas.

Ionic Radius

The ionic radius of an element is the distance between the center of its nucleus and the outermost electron in an ion formed from that element. Oganesson, being an inert gas, does not form ions easily, but some of its isotopes have been observed to have partially ionic character.

The covalent interaction of oganesson with other elements is yet to be studied due to its rarity and instability. Therefore, its ionic radius is not well established.

However, its isotopes that have a partially ionic character are known to have ionic radii similar to those of the other noble gases.

Oganesson Isotopes and Electronic Shell


Isotopes of an element are atoms that have the same number of protons but different numbers of neutrons in their nuclei. For oganesson, various isotopes have been synthesized in the laboratory.

However, due to their radioactive nature and short half-lives, these isotopes are highly unstable and decay rapidly into other elements. Among the synthesized isotopes of oganesson, Og-294 is the most stable and longest-lived isotope, with a half-life of about 0.7 milliseconds.

Other isotopes, such as Og-295 and Og-296, have half-lives in the range of microseconds. The study of oganesson isotopes is challenging due to their short-lived nature, but their synthesis provides valuable data about the behavior and properties of superheavy elements.

Electronic Shell

The electronic shell of an atom describes the organization and arrangement of electrons around the atomic nucleus. It is characterized by the principal quantum number, which corresponds to the energy level at which the electrons reside.

The first shell, closest to the nucleus, is assigned the principal quantum number n = 1, and subsequent shells have higher values of n. In oganesson, the electron configuration follows the principles established by the Aufbau principle, which states that electrons fill the lowest energy levels first before moving to higher levels.

The electronic shell of oganesson can be described by the filling of the s, p, d, and f orbitals. In the case of oganesson, the electron configuration is [Rn] 5f14 6d10 7s2 7p6, where [Rn] represents the electron configuration of radon, which occupies the previous period.

The valence electrons, which are the electrons in the outermost shell, play a significant role in determining the chemical behavior of an element. In oganesson, the valence shell consists of the 7p subshell, which can hold up to six electrons.

However, oganesson has only one electron in its valence shell, making it highly reactive compared to other noble gases.

Oganesson Electron Configurations and Ionization Energy

Electron Configurations

The electron configuration of an element describes the arrangement of electrons within its shells and subshells. In oganesson, the filling of the electron orbitals follows the Aufbau principle, where electrons occupy lower energy levels before filling higher energy levels.

For oganesson, the electron configuration is [Rn] 5f14 6d10 7s2 7p6. This configuration indicates that oganesson has a completely filled 7p subshell, making it stable and less likely to form chemical bonds.

The full occupancy of the 7p subshell contributes to its inertness, similar to other noble gases.

Ionization Energy

Ionization energy refers to the energy required to remove an electron from an atom or ion. It is a measure of an element’s ability to lose or gain electrons.

Elements with low ionization energies are more likely to form positive ions, while those with high ionization energies tend to form negative ions. As an inert gas, oganesson has a high ionization energy, similar to the other noble gases.

This high ionization energy is due to the stability resulting from the complete occupancy of its valence shell. By removing an electron from the fully-filled 7p subshell, oganesson would disrupt its stable electron configuration, making it energetically unfavorable.

Oganesson’s high ionization energy contributes to its chemical inertness, as it is unlikely to readily form ions or engage in chemical reactions.

Oganesson Oxidation States, CAS Number and Chem Spider ID

Oxidation States

Oxidation states, also known as oxidation numbers, represent the hypothetical charges an atom would possess if it were to gain or lose electrons in a chemical compound. While the oxidation states of most elements can be determined based on their valence electrons and electronegativity, the oxidation states of oganesson are not well-established due to its rarity and instability.

As an inert gas and part of the noble gas group, oganesson is typically considered to have a zero oxidation state, which signifies its stable and unreactive nature. However, some theoretical studies suggest that oganesson might be able to exhibit variable oxidation states, especially when interacting with highly electronegative atoms, though these predictions are still speculative and require further experimental validation.

CAS Number and Chem Spider ID

The Chemical Abstracts Service (CAS) number is a unique numerical identifier assigned to each chemical substance, providing a standardized way of referencing and cataloging chemical compounds. However, oganesson, being a synthetic and highly unstable element, does not have a CAS number specifically assigned to it.

Similarly, Chem Spider, a chemical structure database, does not have a specific entry for oganesson due to its limited availability and rapidly decaying nature. Chem Spider primarily focuses on cataloging and providing data for stable compounds and well-characterized chemical substances.

Oganesson’s unique properties and scarcity make it challenging to assign specific references such as CAS numbers and Chem Spider IDs, as its characterization and studies continue to be limited by its synthetic production.

Oganesson Allotropic Forms, Chemical Classification, and State at Room Temperature

Allotropic Forms

Allotropy refers to the phenomenon where an element can exist in different physical forms or arrangements, known as allotropes. However, due to its synthetic production and limited study, oganesson’s allotropic forms have not been experimentally observed or documented.

The stability and existence of allotropic forms depend on factors such as interatomic forces, environmental conditions, and catenation property, which refers to an element’s ability to form extended chains or networks of atoms through covalent bonding. As for oganesson, its properties and behavior suggest that it might not exhibit distinct allotropic forms, or any variations would be highly challenging to investigate.

Chemical Classification

Oganesson belongs to the group of noble gases or inert gases in the periodic table. Noble gases are highly stable and chemically unreactive due to their full valence shells, making them unlikely to form compounds with other elements.

Oganesson’s placement in the noble gas group indicates its similarity to other elements in terms of chemical behavior and inertness.

State at Room Temperature

At standard temperature and pressure, oganesson is expected to exist in the gaseous state. Being a noble gas, it lacks intermolecular forces caused by dipole-dipole interactions or hydrogen bonding, leading to its low boiling and melting points.

The relativistic effect, which arises from the high speeds of electrons in heavy elements, also contributes to the increased stability and reduced reactivity of oganesson. Due to its short half-life and rarity, oganesson is challenging to study experimentally.

As a result, its exact state at room temperature and other physical properties have not been conclusively determined. Further experimental research and advancements are necessary to deepen our understanding of oganesson’s behavior under varying conditions.

Oganesson Paramagnetism


Paramagnetism refers to the phenomenon where certain materials are weakly attracted to magnetic fields. It occurs as a result of unpaired electrons in the atoms or molecules of a substance.

When a magnetic field is applied, the unpaired electrons align their magnetic moments with the field, leading to a magnetization of the material. In the case of oganesson, which is in the noble gas group, all its electrons are paired within its electron configuration of [Rn] 5f14 6d10 7s2 7p6.

This implies that oganesson does not have any unpaired electrons, and therefore it is not inherently paramagnetic like many other materials.


Diamagnetism is another type of magnetism that occurs in all materials, including oganesson, regardless of whether they possess paired or unpaired electrons. Unlike paramagnetism, diamagnetism refers to the weak repulsion experienced by atoms or molecules when placed in a magnetic field.

In diamagnetic materials, orbital and spin contributions from paired electrons result in opposing magnetic fields within the atoms or molecules, causing a net magnetic moment of zero. This causes the material to be weakly repelled from the magnetic field.

Since oganesson possesses a complete electron configuration with all electrons paired, it exhibits diamagnetic behavior. However, the molar magnetic susceptibility, which quantifies the extent to which a material exhibits diamagnetism, is currently unknown for oganesson due to its limited study and short half-life.

It is important to note that the diamagnetic effect in oganesson is typically much weaker than the paramagnetic effect in paramagnetic materials due to the absence of unpaired electrons. Nonetheless, diamagnetism highlights the fundamental magnetic properties that exist in all materials, including those with completely filled electron configurations like oganesson.


In conclusion, this article has explored the fascinating properties of oganesson, the heaviest element in the periodic table.

From its radioactive nature to its position in the periodic table as a noble gas, oganesson stands out as a rare and intriguing element. While its isotopes have been synthesized in the lab, their short lifespans and limited availability pose challenges for further study.

Nevertheless, understanding oganesson’s characteristics, such as its electronic shell and diamagnetic behavior, expands our knowledge of the periodic table and highlights the fundamental principles governing the behavior of elements. Oganesson serves as a reminder of the ongoing quest to explore the uncharted territories of the chemical world and pushes the boundaries of human knowledge.


  1. What is oganesson?
  2. Oganesson is a synthetic and radioactive element, with properties that make it unusual and scientifically significant.

  3. What is the position of oganesson in the periodic table?
  4. Oganesson belongs to the noble gas group in Group 18 of the periodic table, known for its inert and unreactive nature.

  5. Does oganesson have any stable isotopes?
  6. No, oganesson does not have any stable isotopes, and the synthesized isotopes have extremely short half-lives.

  7. Is oganesson paramagnetic or diamagnetic?
  8. Oganesson exhibits diamagnetic behavior due to the pairing of all its electrons, resulting in weak repulsion when exposed to a magnetic field.

  9. Does oganesson have a CAS number or Chem Spider ID?
  10. Due to its limited availability and synthetic production, oganesson does not have a specific CAS number or Chem Spider ID.

  11. What is the significance of studying oganesson?
  12. Studying oganesson helps expand our understanding of the periodic table, the properties of superheavy elements, and the fundamental principles guiding chemical behavior.

Final thought: Oganesson’s unique and mysterious nature challenges our understanding of the chemical world, emphasizing the vast potential for discovery and the continuous pursuit of knowledge in the scientific realm.

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