Introduction to Oganesson
Oganesson (Og), with atomic number 118, is a synthetic chemical element, meaning it does not occur naturally on Earth and is produced only in laboratories through nuclear reactions. It is a superheavy element and the heaviest element currently known on the periodic table. Oganesson is named after Yuri Oganessian, a prominent Russian nuclear physicist, recognizing his significant contributions to the discovery of superheavy elements. It belongs to Group 18 of the periodic table, classifying it as a noble gas. Due to its extreme instability and extremely short half-life (milliseconds), only a few atoms of Oganesson have ever been produced, primarily at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. Its chemical properties are largely theoretical and extrapolated from its position in the periodic table.
Atomic Number and Mass Number
The atomic number (Z) of an element defines its identity and is equal to the number of protons in the nucleus of an atom. For Oganesson, the atomic number is 118.
The mass number (A) of an atom is the total number of protons and neutrons in its nucleus. The most stable known isotope of Oganesson is Oganesson-294. Therefore, its mass number is 294.
Subatomic Particles in Oganesson
Protons
The number of protons in an atom is determined by its atomic number. Since the atomic number of Oganesson is 118, an atom of Oganesson contains 118 protons.
Neutrons
The number of neutrons in an atom can be calculated by subtracting the atomic number (Z) from the mass number (A). For the isotope Oganesson-294:
Number of neutrons = Mass number (A) - Atomic number (Z) Number of neutrons = 294 - 118 = 176 neutrons.
Electrons
In a neutral atom, the number of electrons is equal to the number of protons to balance the positive charge of the nucleus. Therefore, a neutral atom of Oganesson contains 118 electrons.
Electron Configuration of Oganesson
The electron configuration describes the arrangement of electrons in the atomic orbitals around the nucleus. For Oganesson (atomic number 118), the electron configuration is very extensive. A condensed notation, using the symbol of the preceding noble gas, is often used for heavier elements. The preceding noble gas is Radon (Rn), with atomic number 86.
The electron configuration of Oganesson is theoretically predicted as:
[Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶
Breaking this down:
- [Rn]: Represents the electron configuration of Radon (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶), accounting for 86 electrons.
- 5f¹⁴: After Radon, the 5f subshell is filled with 14 electrons.
- 6d¹⁰: Following the 5f subshell, the 6d subshell is filled with 10 electrons.
- 7s²: The 7s subshell is filled with 2 electrons.
- 7p⁶: Finally, the 7p subshell is filled with 6 electrons.
This complete filling of the 7p subshell leads to a very stable configuration, characteristic of a noble gas.
Valence Electrons in Oganesson
Valence electrons are the electrons located in the outermost shell (the highest principal energy level) of an atom. These electrons are primarily involved in chemical bonding and determine an element’s chemical properties.
For Oganesson, the outermost principal energy level is the 7th shell. The electrons in this shell are those in the 7s and 7p subshells.
Number of valence electrons = Electrons in 7s subshell + Electrons in 7p subshell Number of valence electrons = 2 + 6 = 8 valence electrons.
This presence of 8 valence electrons (a complete octet in its outermost shell) theoretically classifies Oganesson as a noble gas, suggesting it would be chemically unreactive, similar to other elements in Group 18 like Neon or Argon.