Final answer:
To rank the ions Br-, As3-, Cl-, and Rb+ in terms of ionic radii, we consider their positions in the periodic table and their charges. The ions are arranged as Cl- < Br- < Rb+ < As3- with the chloride ion being the smallest due to fewer electrons and the arsenide ion being the largest due to most added electrons and least nuclear charge effect.
Step-by-step explanation:
The question involves ranking ions according to their ionic radii. To do this, we consider the position of each ion in the periodic table as well as the number of protons and electrons to discern the ionic size trends. Considering the ions Br−, As3−, Cl−, and Rb+, we'll arrange them in order of increasing ionic radius.
First, it's important to note that as we move down a group in the periodic table, the ionic radius increases due to the addition of electron shells. Also, for ions with the same charge, the ionic radius decreases with an increase in the number of protons due to greater nuclear charge pulling the electrons closer. Keeping these rules in mind, here is the correct order:
- Cl− (17 protons) smaller than
- Br− (35 protons) smaller than
- Rb+ (37 protons but has lost an electron to become a cation, so it's larger than Br−) smaller than
- As3− (33 protons but has gained three electrons, making it the largest due to repulsion between added electrons and the least nuclear charge effect)
- This understanding of how ionic size changes based on position in the periodic table and charge can help in ranking ions correctly.