what is the lewis dot structure for SeOBr2? And is it polar or non polar?
The correct answer and explanation is:
Lewis Dot Structure of SeOBr₂:
- Count the valence electrons:
- Selenium (Se): 6 valence electrons.
- Oxygen (O): 6 valence electrons.
- Bromine (Br): Each has 7 valence electrons (2 Br atoms).
- Total valence electrons = 6+6+(7×2)=266 + 6 + (7 \times 2) = 26.
- Determine the central atom:
- Selenium is less electronegative than oxygen and bromine, so it is the central atom.
- Form single bonds:
- Connect Se to O and each Br with single bonds, using 2 electrons per bond.
- Electrons used = 3×2=63 \times 2 = 6.
- Distribute remaining electrons:
- Complete the octets of the outer atoms (O and Br atoms).
- Oxygen gets 6 electrons, and each bromine gets 6 electrons. Electrons used = 6+6+6=186 + 6 + 6 = 18.
- Place remaining electrons on Se:
- Selenium now gets the remaining 2 electrons as a lone pair.
- Check formal charges:
- The structure has no formal charges, making it stable.
Lewis Structure:
- Selenium has one lone pair.
- Oxygen is double-bonded to Selenium.
- Two Bromine atoms are single-bonded to Selenium.
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O
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Br-Se-Br
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Polarity:
SeOBr₂ is polar.
- The molecule has a bent geometry due to the lone pair on Selenium, giving it an asymmetrical shape.
- Oxygen is more electronegative than Bromine, creating a dipole moment. The dipoles do not cancel out because of the molecule’s shape, making it polar.
Explanation :
The Lewis dot structure of SeOBr₂ shows how valence electrons arrange around the atoms to form bonds while following the octet rule. Selenium, as the central atom, forms bonds with one oxygen and two bromine atoms. The oxygen forms a double bond with Selenium, while each bromine forms a single bond. A lone pair of electrons resides on Selenium, resulting in a total of 26 valence electrons in the molecule.
The molecular geometry of SeOBr₂ is bent (angular) due to the lone pair on Selenium, which repels the bonded electron pairs and causes the bond angles to deviate from 120° (trigonal planar ideal angles). The presence of the lone pair also contributes to the molecule’s asymmetry.
Polarity in molecules depends on both the electronegativity differences between bonded atoms and the symmetry of the molecule. Oxygen, being more electronegative than Bromine, creates a stronger pull on the shared electrons, resulting in a partial negative charge around the oxygen atom. The bent shape prevents the dipoles from canceling out, so the molecule has a net dipole moment. Therefore, SeOBr₂ is polar.
This polarity impacts its physical and chemical properties, such as solubility and reactivity. Polar molecules like SeOBr₂ tend to dissolve well in polar solvents (e.g., water) and have higher boiling and melting points compared to nonpolar molecules of similar size.