Group 16 Elements

Concept: Ionic radius increases down a group due to the addition of new electron shells.

Step 1: Group 15 elements (Nitrogen family).

Step 2: Trend for anions . Down the group, the number of shells increases, so ionic radius increases:

Concept: Ozone ( ) is a strong oxidizing agent.

Step 1: Reaction.

Step 2: Observation.

Step 3: Conclusion. Liberated iodine turns starch paper blue.

Concept: Group 15 elements form pentahalides if they can expand their octet by using available d-orbitals.

Step 1: Check each element.
N (Nitrogen) No d-orbitals in valence shell, cannot expand octet
P (Phosphorus) Has 3d-orbitals, forms
As (Arsenic) Has 4d-orbitals, forms
Sb (Antimony) Has 5d-orbitals, forms
Bi (Bismuth) Has 6d-orbitals, forms

Step 2: Count.


Step 3: Conclusion.
Thus, number of elements that form pentahalides = 4.