What is the correct Lewis structure for N2?
A) N-N
B) :-:
C) =
D) : N ≡ N :
E) none of the above
The Correct answer and Explanation is:
The correct Lewis structure for nitrogen gas (N₂) is option D) : N ≡ N :.
Explanation of the Lewis Structure for N₂
- Understanding Nitrogen: Each nitrogen atom has five valence electrons, and since there are two nitrogen atoms in N₂, the total number of valence electrons available is 5+5=105 + 5 = 105+5=10 electrons.
- Bonding Requirements: To achieve a stable electron configuration, nitrogen tends to form three bonds, leading to a complete octet (8 electrons in its outer shell). This bonding preference is due to nitrogen’s position in Group 15 of the periodic table, where it typically shares or gains electrons to achieve stability.
- Single vs. Multiple Bonds: The simplest way to connect two nitrogen atoms is through a single bond (N-N), which would involve only two shared electrons. However, this does not satisfy the octet rule for either nitrogen atom, as each would still have only six electrons in its outer shell. A double bond (N=N) involves four shared electrons, but each nitrogen would still have only seven electrons around it, which is also insufficient for stability.
- Triple Bond Formation: The optimal configuration for N₂ is a triple bond, represented as N≡N. In this arrangement, three pairs of electrons (six electrons total) are shared between the two nitrogen atoms. Each nitrogen atom then has a total of eight electrons in its valence shell: the three bonding pairs (six electrons) plus the one lone pair (two electrons) that remains on each nitrogen atom.
- Final Structure: In the Lewis structure representation, the triple bond is depicted as three lines connecting the nitrogen atoms, often with a lone pair of dots on each nitrogen. This gives the structure : N ≡ N :. This triple bond not only satisfies the octet rule for both atoms but also accounts for the high bond energy and stability observed in nitrogen gas.
In conclusion, the correct Lewis structure for nitrogen gas, which fulfills the octet rule for both nitrogen atoms, is D) : N ≡ N :.