Answer the question on basis of passage given below:

Nitrogen differs from the rest of the members of its group due to its small size, high electronegativity, high ionisation enthalpy and non-availability of d-orbitals. Nitrogen has unique ability to form $pπ-pπ$ multiple bonds with itself and with other elements having small size and high electronegativity (eg, C, O) Heavier elements of this group do not form $pπ-pπ$ bonds as their atomic orbitals are so large and diffused that they cannot have effective overlapping.

Maximum covalency of Nitrogen is:

4

The correct answer is Option 3. 4

Let us delve deeper into the concept of maximum covalency of nitrogen, examining the underlying principles, examples, and chemical behavior step by step.

Step 1: Understanding Covalency

Covalency refers to the number of pairs of electrons shared between atoms in a molecule. It indicates how many bonds an atom can form through the sharing of electrons. Each bond corresponds to one pair of shared electrons. Covalency is crucial for determining the structure and reactivity of molecules.

Step 2: Analyzing the Valence Electrons of Nitrogen

Nitrogen's Electron Configuration: Nitrogen (N) is in Group 15 of the periodic table. Its electronic configuration is \(1s^2 2s^2 2p^3\).

Valence Electrons: It has 5 valence electrons (2 from the \(2s\) and 3 from the \(2p\) orbitals). To achieve a full octet (8 electrons), nitrogen needs to share or gain 3 more electrons.

Step 3: Determining the Maximum Covalency

Single Bonds: A single bond involves one pair of electrons. Nitrogen can form a single bond with another atom (e.g., \( \text{NH}_3 \)).

Double Bonds: A double bond involves two pairs of electrons. Nitrogen can participate in double bonding (e.g., \( \text{N}_2\text{O}_2 \)).

Triple Bonds: A triple bond consists of three pairs of electrons (e.g., \( \text{N}_2 \) itself).

While theoretically, nitrogen can form a triple bond, it can also utilize its lone pair of electrons to form additional bonds, particularly in certain compounds.

Step 4: Examples of Covalency in Compounds

Ammonia (\( \text{NH}_3 \)):

In ammonia, nitrogen forms three single bonds with three hydrogen atoms, utilizing three of its valence electrons. It retains one lone pair.

Covalency: 3

2. Nitrogen Dioxide (\( \text{NO}_2 \)):

In nitrogen dioxide, nitrogen forms one double bond with one oxygen and a single bond with another oxygen. This leads to a total of four pairs of electrons being shared.

Covalency: 4

3. Dinitrogen Pentoxide (\( \text{N}_2\text{O}_5 \)):

In \( \text{N}_2\text{O}_5 \), each nitrogen atom forms two double bonds with oxygen atoms, effectively sharing four pairs of electrons (two pairs for each nitrogen).

Covalency: 4

4. Other Examples:

Nitrate Ion (\( \text{NO}_3^- \)): Nitrogen forms one double bond with one oxygen and two single bonds with two other oxygens, resulting in a total of four covalent interactions.

Covalency: 4

Step 5: Conclusion

The maximum covalency of nitrogen is often considered 4 based on its common bonding patterns in stable compounds. While nitrogen has the potential to exhibit covalency up to 5 in specific contexts (like in certain coordination compounds), the typical and practical maximum in most chemical scenarios is 4.

Summary

Maximum Covalency: 4

Common Compounds: \( \text{NH}_3 \), \( \text{NO}_2 \), \( \text{N}_2\text{O}_5 \), \( \text{NO}_3^- \)