Which one of the following alternatives lists the atoms of chlorine, fluorine, magnesium and potassium in order of increasing atomic radius? A - VCE - SSCE Chemistry - Question 17 - 2006 - Paper 1

In the periodic table, atomic radius generally increases down a group and decreases across a period from left to right. Since K and Mg are in period 3 while Cl and F are in period 2, we expect K to have a larger atomic radius than both Cl and F.

Considering the trends:

1. Fluorine (F) is the smallest due to its high electronegativity and position in period 2.
2. Chlorine (Cl) is larger than fluorine but smaller than the metals Mg and K.
3. Magnesium (Mg) is larger than Cl but smaller than potassium (K).
4. Potassium (K) is the largest as it is in a lower period (period 4).

Thus, the order from smallest to largest is: F < Cl < Mg < K.

Based on the determined order, the correct alternative is D: (smallest) F, Cl, Mg, K (largest).