An electron is a subatomic particle that carries a negative electrical charge, orbiting the dense, positively charged nucleus of an atom. The arrangement and number of electrons surrounding the nucleus dictate an atom’s chemical behavior and how it will interact with other atoms. In fact, the outer shell electrons are responsible for nearly all of the chemical bonding that forms the molecules and materials we encounter every day.
The Role of Atomic Number in Electron Count
The number of electrons an atom possesses is fundamentally tied to its atomic number, which is represented by the symbol Z. The atomic number is defined as the exact number of protons found within the nucleus, which uniquely identifies an element. For an atom to be electrically neutral, the total negative charge from its electrons must perfectly balance the total positive charge from its protons.
This requirement means that in a neutral atom, the number of electrons is precisely equal to the atomic number (Z). For instance, an atom with an atomic number of 8, which is oxygen, will contain exactly eight protons and eight electrons. Atoms that have either gained or lost electrons, resulting in an unequal number of protons and electrons, are known as ions and carry a net electrical charge.
The Current Element with the Most Electrons
The element that currently holds the record for the most electrons in its neutral state is Oganesson (Og). This element has the highest confirmed atomic number, Z=118, meaning a neutral Oganesson atom possesses 118 electrons. Oganesson is classified as the final element in the seventh row and the final member of the noble gas group on the current periodic table.
Oganesson was first successfully synthesized in 2002 by a joint team of Russian and American scientists. Although its placement suggests it should be a gas like other noble elements, theoretical calculations suggest its high electron count and the resulting relativistic effects on those electrons could make it a solid at room temperature. Only a handful of atoms of Oganesson have ever been produced and studied due to the extreme difficulty of its creation.
The Instability of Superheavy Elements
Elements with extremely high electron counts, such as Oganesson, are known as superheavy elements, and they are inherently unstable. All elements with atomic numbers greater than 82, which is lead, lack any stable isotopes. Oganesson is particularly unstable because it is synthetic, and its most stable known isotope, Oganesson-294, has an extremely short half-life of only about 0.7 milliseconds.
The instability increases rapidly after element 96, curium, because the powerful electrical repulsion between the large number of positive protons overwhelms the strong nuclear force that holds the nucleus together. Scientists continue to search for the next theoretical element, Ununennium (Z=119), which would start the eighth row of the periodic table. The search for these new elements is driven by the concept of the “Island of Stability,” a theoretical region where certain combinations of protons and neutrons may lead to a temporary increase in nuclear stability.
This hypothetical island suggests that superheavy elements could exist with half-lives measurable in minutes, days, or even longer, far exceeding the milliseconds seen in Oganesson. While the exact center of this island is still debated, possibly around Z=114 or Z=126, the confirmed existence of elements like Oganesson shows that the stabilizing effects predicted by theory are real. The pursuit of the Island of Stability represents the limit of how many electrons an element can realistically hold for a measurable duration.