Question

The maximum covalency of a non-metallic group 15 element 'E' with the weakest E-E bond is:

• A. 6
• B. 5
• C. 3
• D. 4

Hint:

The maximum covalency of Group 15 elements can be influenced by their size and the availability of d-orbitals for bonding. For example, nitrogen typically has a maximum covalency of 3, while heavier elements like phosphorus can reach a maximum covalency of 4.

Answer 1

The Correct Option is D

To identify the maximum covalency of a non-metallic Group 15 element possessing the weakest E-E bond, we must define covalency and examine Group 15 bonding characteristics.

Step 1: Covalency Definition

Covalency signifies an atom's capacity to share electron pairs with others. For Group 15 elements (Nitrogen, Phosphorus, Arsenic, Antimony, Bismuth), non-metals typically form covalent bonds through electron sharing.

Step 2: Group 15 Elements and Covalency

Group 15 elements possess five valence electrons. Maximum covalency generally corresponds to the number of unpaired valence electrons, potentially exceeding the octet rule when d-orbitals are involved, particularly in heavier elements of this group.

Step 3: Weakest E-E Bond Analysis

Nitrogen (N₂) exhibits a very strong triple bond, disqualifying it from having the weakest E-E bond. Phosphorus, conversely, tends to form P₄ structures with relatively weaker single P-P bonds, making it a candidate.

Step 4: Phosphorus Covalency

Phosphorus can achieve a covalency of 5 by utilizing d-orbitals, as seen in PF₅. However, considering typical bonding without d-orbital expansion, the practical maximum observed covalency is 4, exemplified by the PCl₄⁺ ion.

Conclusion: The maximum covalency of phosphorus, a non-metallic Group 15 element with the weakest E-E bond among suitable candidates, is 4.