The van der Waals radius is largest in Cl (Chlorine).
Understanding Van der Waals Radii
The van der Waals radius represents half the distance between the nuclei of two identical, non-bonded atoms in a molecule, when their outermost electron shells are in contact but not overlapping chemically. It's essentially a measure of how much space an atom occupies when it's not bonded to others.
Why Chlorine Has the Largest Radius
Based on the provided reference information, the comparison is among Ne, O, F, and Cl.
- Ne, O, and F are elements found in the second period of the periodic table.
- Cl is an element found in the third period of the periodic table.
As atoms move down a group in the periodic table, they gain additional electron shells. These extra shells significantly increase the overall size of the atom, including its van der Waals radius. The reference explicitly states: "Ne, O and F are the second period elements while Cl is 3rd period element so has the largest van der waals radius."
Therefore, because Chlorine is in a higher period (period 3) compared to Neon, Oxygen, and Fluorine (all in period 2), it possesses more electron shells and consequently a larger van der Waals radius.
Here's a simple breakdown:
- Oxygen (O): Period 2
- Fluorine (F): Period 2
- Neon (Ne): Period 2
- Chlorine (Cl): Period 3
General Trends
While the primary factor here is the move to a higher period, it's useful to note the general trend:
- Across a period (left to right): Van der Waals radius generally decreases.
- Down a group (top to bottom): Van der Waals radius generally increases.
Comparing elements within the same period, the noble gas typically has the largest van der Waals radius due to its complete electron shell and weaker interatomic forces compared to bonded atoms of other elements. However, when comparing elements from different periods, the increase in electron shells going down a group has a more significant impact on size. In this specific set, moving from period 2 to period 3 (from Ne, O, F to Cl) dictates the increase in radius.
