Question

use the periodic table to rank the orange elements from smallest to largest. * (0.5 points)

Explanation:

Step1: Recall atomic radius trends

Atomic radius increases down a group and decreases across a period.

Step2: Analyze positions

Ca is in period 4, group 2. Rb is in period 5, group 1. Sr is in period 5, group 2.
Since Ca is above Sr (same group, higher period means larger radius for Sr). Rb is in group 1 (left of Sr in same period, group 1 elements have larger radius than group 2 in same period).

Answer:

Ca < Sr < Rb