Answer: P3-, S2-, Cl-, K+, Ca2+
Step-by-step explanation:
All of the ions are isoelectronic, so the largest ions will be the ones with extra repulsion between their electrons due to the presence of additional electrons that decrease the Zeff of the valence electrons of the ion, increasing the distance between the valence electrons and the nucleus and the ionic radius. Positive ions represent a deficiency in electrons, and their positive charge strongly attracts the electrons, causing them to be close to the nucleus, thus making their ionic radius small.
With the ionic radius patterns for charges, the largest ion will be the most negative one and the following ions will become less and less negative until we reach the smallest ion, which will be the most positive ion.
Thus, the answer is P3-, S2-, Cl-, K+, Ca2+