Final answer:
An isoelectronic series consists of atoms or ions that share the same electron configuration but have different nuclear charges.
Step-by-step explanation:
A series that includes two or more species with identical electron configurations but different nuclear charges is known as an isoelectronic series. These species have the same ground-state electron configuration due to having the same number of electrons, yet they differ in terms of their atomic numbers. An example of such a series could be N³⁻, O²⁻, F⁻, Ne, Na⁺, Mg²⁺, and Al³⁺, which all have the electron configuration of 1s²2s²2p⁶.
Another isoelectronic series is P³⁻, S²⁻, Cl⁻, Ar, K⁺, Ca²⁺, and Sc³⁺, which follow the electron configuration of [Ne]3s²3p⁶. In these series, the nuclear charge, which is the number of protons in the nucleus, determines the size of the atom or ion. The larger the nuclear charge, the smaller the radius, due to a stronger attraction between the protons and the electrons. Examples include species with electron configurations of 1s²2s²2p⁶ and [Ne]3s²3p⁶. The size of each atom or ion in such a series is determined by its nuclear charge, with larger charges resulting in smaller radii.