Q
QuestionChemistry

Of the two compounds, SiF^4 ​ and SF^4, which is polar and which is nonpolar?
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Answer

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Step 1:
I'll solve this problem step by step, focusing on molecular geometry and polarity.

Step 2:
: Determine the Lewis structure and electron geometry for SiF^4

- Total valence electrons: $$4 + (4 \times 7) = 32$$ electrons
- Silicon (Si) is the central atom - Silicon has 4 valence electrons - Fluorine (F) has 7 valence electrons - Arrangement will be tetrahedral with 4 identical Si-F bonds

Step 3:
: Analyze the molecular geometry of SiF^4

- Bond angles are $$109.5^\circ
- Central Si atom has 4 identical F atoms - Molecular geometry is tetrahedral

Step 4:
: Analyze bond polarity in SiF^4

- Si-F bonds are polar due to electronegativity difference - Fluorine is much more electronegative than silicon - However, the tetrahedral symmetry causes dipoles to cancel

Step 5:
: Determine polarity of SiF^4

- Despite polar bonds, the overall molecule is nonpolar - Symmetrical tetrahedral structure results in net zero dipole moment

Step 6:
: Repeat analysis for SF^4

- Total valence electrons: $$6 + (4 \times 7) = 34$$ electrons
- Sulfur (S) is the central atom - Sulfur has 6 valence electrons - Fluorine has 7 valence electrons

Step 7:
: Analyze SF^4 molecular geometry

- Central S atom has 4 F atoms - Molecular geometry is see-saw (distorted tetrahedral) - Asymmetric arrangement means unequal dipole cancellation

Step 8:
: Determine polarity of SF^4

- S-F bonds are polar - Asymmetric molecular geometry - Net dipole moment exists - SF^4 is polar

Final Answer

- SiF^4: Nonpolar - SF^4: Polar