Molecule or lon Lewis Structure Formula Type Molecular Shape Shape Name (Molecular Geometry) Polarity – IF polar show dipoles* :O: 2- O=C-O CO32- :O: PO43- :O: :O-P-O: || :O: 3- SCN- S=C=N H2CO3 H-O-C-O-H OMIT OMIT OMIT OMIT :O: * If not polar write “non-polar”
The Correct Answer and Explanation is:
Here is the completed table with correct molecular properties:
| Molecule or Ion | Lewis Structure | Formula Type | Molecular Shape | Shape Name (Molecular Geometry) | Polarity | ||
|---|---|---|---|---|---|---|---|
| CO3²⁻ | :O: O=C-O :O: | Polyatomic ion | Trigonal planar | Trigonal planar | Non-polar | ||
| PO4³⁻ | :O: :O-P-O: | :O: | Polyatomic ion | Tetrahedral | Tetrahedral | Non-polar | |
| SCN⁻ | S=C=N | Polyatomic ion | Linear | Linear | Polar (dipoles present) | ||
| H2CO3 | H-O-C-O-H :O: | OMIT | OMIT | OMIT | OMIT |
Explanation
The molecular geometry and polarity of these species are determined based on their Lewis structures and electron domain arrangements. Carbonate ion (CO3²⁻) has a central carbon atom bonded to three oxygen atoms. Since it experiences resonance, the bonds are equivalent, and the molecular shape is trigonal planar with bond angles of approximately 120 degrees. The dipoles cancel out due to the symmetric structure, making it non-polar.
Phosphate ion (PO4³⁻) consists of a phosphorus atom bonded to four oxygen atoms. The molecular geometry follows a tetrahedral arrangement with bond angles of about 109.5 degrees. Due to its symmetrical distribution of charge, it is non-polar.
The thiocyanate ion (SCN⁻) is linear, consisting of sulfur, carbon, and nitrogen atoms in a straight arrangement. Because sulfur and nitrogen have different electronegativities, the bond dipoles do not cancel out, making the ion polar.
Carbonic acid (H2CO3) is omitted from further analysis in the table. However, it consists of a central carbon bonded to two hydroxyl groups and an oxygen atom in a trigonal planar arrangement. It typically exhibits polarity due to the asymmetrical placement of hydroxyl groups.
Understanding molecular shapes and polarity is crucial for predicting physical properties, solubility, and chemical reactivity. These factors influence interactions in biological systems, industrial processes, and environmental chemistry.
