Which of the following will have the largest radius?a. Al+3     b. P-3     c. S-2    d. Cl-1

To determine which of the given ions will have the largest radius, we need to consider their respective atomic numbers and charges.

a. Al+3: Aluminum (Al) has an atomic number of 13 and a charge of +3. b. P-3: Phosphorus (P) has an atomic number of 15 and a charge of -3. c. S-2: Sulfur (S) has an atomic number of 16 and a charge of -2. d. Cl-1: Chlorine (Cl) has an atomic number of 17 and a charge of -1.

In general, as we move across a period in the periodic table, the atomic radius decreases due to an increase in the number of protons in the nucleus. Conversely, as we move down a group, the atomic radius increases due to the addition of new energy levels.

Comparing the given ions, we can see that Al+3 has the smallest atomic number and the highest positive charge. This means that Al+3 has lost three electrons, resulting in a smaller radius compared to its neutral atom.

On the other hand, P-3, S-2, and Cl-1 have gained three, two, and one electrons, respectively. This means that these ions have increased in size compared to their neutral atoms.

Therefore, among the given options, the ion with the largest radius is b. P-3 (Phosphorus with a charge of -3).