write lewis structures of nf3. what is the electronic and molecular geometry? is the molecule polar or non-polar? explain your answer.
The Correct Answer and Explanation is :
The correct answer is: polar molecule
Lewis Structure of NF₃ (Nitrogen Trifluoride)
To draw the Lewis structure of NF₃:
- Count the Valence Electrons:
- Nitrogen (N) has 5 valence electrons.
- Each Fluorine (F) has 7 valence electrons, and there are three fluorine atoms.
- Total: (5 + (3 \times 7) = 5 + 21 = 26) valence electrons.
- Arrange the Atoms:
- Place the nitrogen atom in the center and surround it with three fluorine atoms.
- Form Bonds:
- Connect each fluorine to the nitrogen with a single bond (2 electrons per bond). This uses (3 \times 2 = 6) electrons.
- Distribute Remaining Electrons:
- After forming bonds, (26 – 6 = 20) electrons remain. Each fluorine needs 6 more electrons (3 lone pairs) to complete its octet. This uses (3 \times 6 = 18) electrons, leaving 2 electrons.
- Place Remaining Electrons on Nitrogen:
- The nitrogen atom will have one lone pair of electrons.
The resulting Lewis structure is:
F
|
F--N--F
|
:N:In this representation, the dots (:) represent the lone pair on the nitrogen atom.
Electronic and Molecular Geometry
- Electronic Geometry: Based on the number of regions of electron density (bonding and lone pairs), NF₃ has four regions (three N-F bonds and one lone pair). This gives it a tetrahedral electronic geometry.
- Molecular Geometry: Considering only the bonded atoms (ignoring the lone pair), NF₃ adopts a trigonal pyramidal molecular geometry.
Polarity of NF₃
NF₃ is a polar molecule. This can be explained as follows:
- Electronegativity Differences: Fluorine is more electronegative than nitrogen, which creates a dipole moment as the electrons are pulled closer to the fluorine atoms.
- Asymmetrical Shape: The trigonal pyramidal shape means that the dipoles do not cancel out. The lone pair on nitrogen contributes to the molecular asymmetry, leading to a net dipole moment pointing towards the nitrogen.
In summary, NF₃ has a tetrahedral electronic geometry and a trigonal pyramidal molecular geometry, making it polar due to its uneven distribution of charge.