What is the correct Lewis dot structure for nitrogen trifluoride (NF3)?
The Correct Answer and Explanation is :
The Lewis dot structure for nitrogen trifluoride (NF₃) illustrates the arrangement of electrons around the nitrogen and fluorine atoms in the molecule. In this structure, nitrogen (N) is the central atom, surrounded by three fluorine (F) atoms. The correct Lewis dot structure can be represented as follows:
F
|
F—N—F
|Explanation:
- Valence Electrons Count: To draw the Lewis structure, we first need to determine the total number of valence electrons. Nitrogen has five valence electrons (Group 15), and each fluorine atom has seven valence electrons (Group 17). Thus, for NF₃:
[
\text{Total valence electrons} = 5 + (3 \times 7) = 5 + 21 = 26
] - Central Atom: In NF₃, nitrogen is the central atom because it is less electronegative than fluorine. Fluorine, being highly electronegative, will surround the nitrogen atom.
- Single Bonds Formation: Next, we form single bonds between nitrogen and each of the three fluorine atoms. Each bond consists of two electrons. Therefore, three single bonds account for:
[
3 \text{ bonds} \times 2 \text{ electrons/bond} = 6 \text{ electrons}
] - Distributing Remaining Electrons: After forming the bonds, we subtract the bonded electrons from the total:
[
26 – 6 = 20 \text{ electrons left}
]
We then place three lone pairs (6 electrons) on each fluorine atom, which gives:
[
3 \text{ fluorine atoms} \times 6 = 18 \text{ electrons}
]
After placing the lone pairs, there are no remaining electrons. - Final Structure: Each fluorine atom has three lone pairs and one bonding pair with nitrogen. Nitrogen, in this case, has one lone pair and forms three bonds. The resulting structure is stable, with a full octet around each fluorine atom, while nitrogen has an expanded octet.
This structure ensures that all atoms achieve a stable electron configuration, characteristic of a covalent compound like NF₃.