An isoelectronic series is a group of atoms or ions that have the same number of electrons. This means that they have the same electronic structure and similar properties.
The size of an ion is determined by its atomic radius, which is influenced by the number of electrons and their arrangement. In an isoelectronic series, the ion with the most protons will have the smallest atomic radius, while the ion with the least protons will have the largest atomic radius.
S2- has the largest atomic radius because it has the least amount of protons (16) compared to the other ions in this series. This means that it has the most electrons and the outermost electrons experience less nuclear pull, resulting in a larger atomic radius.
The size of an ion can affect many of its properties, such as its reactivity, solubility, and melting point. Larger ions tend to be less reactive and have lower melting points, while smaller ions tend to be more reactive and have higher melting points.
Understanding isoelectronic series can be useful in chemistry, physics, and even biology. It can help predict the properties and behaviors of different elements and ions, as well as aid in the design of new compounds and materials.