Answer:
Step-by-step explanation:
The order of increasing size (smallest first) among these three negative ions is as follows:
1. Chloride ion (Cl-)
2. Sulfide ion (S2-)
3. Phosphide ion (P3-)
Here's the logic behind this order:
1. **Chloride ion (Cl-):** Chlorine is further to the right on the periodic table compared to sulfur and phosphorus. As you move from left to right across a period of the periodic table, the atomic radius generally decreases due to increasing effective nuclear charge. Since the chloride ion is the smallest, it has the highest effective nuclear charge among these three ions.
2. **Sulfide ion (S2-):** Sulfur is located to the left of chlorine but to the right of phosphorus in the periodic table. It has a larger atomic radius than chlorine. Thus, the sulfide ion is larger than the chloride ion.
3. **Phosphide ion (P3-):** Phosphorus is the furthest to the left on the periodic table among these three ions. It has the largest atomic radius, which makes the phosphide ion the largest among the three.
In summary, the order is determined by the atomic radius trend across the periodic table: Chloride ion < Sulfide ion < Phosphide ion.