Question

directions: solve the problems shown below. any data, calculations, or models you use to support your thinking should be explained. refer to the periodic table below.

1. based on their positions in the periodic table, predict which has the smallest atomic radius: mg, sr, si, cl, i.

mg is in group 2 and period 3
sr group 2 and in period 5.
si is in group 14 and in period 3
cl is in group 17 and period 3
i in group 17 and period 5

Explanation:

Step1: Recall atomic radius trends

Atomic radius decreases across a period (left to right) due to increasing effective nuclear charge, and increases down a group (top to bottom) due to adding electron shells.

Step2: Analyze each element's period and group

• Mg: Group 2, Period 3
• Sr: Group 2, Period 5 (down from Mg, so larger radius)
• Si: Group 14, Period 3 (right of Mg in same period, smaller than Mg)
• Cl: Group 17, Period 3 (right of Si in same period, smaller than Si)
• I: Group 17, Period 5 (down from Cl, larger radius than Cl)

Step3: Compare radii

Across Period 3: Mg (Gr2) < Si (Gr14) < Cl (Gr17). Down Group 17: Cl (Period3) < I (Period5). Down Group 2: Mg (Period3) < Sr (Period5). So Cl is smallest.

Answer:

Cl