Textbook Question
In each pair of atoms, which has the larger atomic radius? Which is more electronegative?
(c) O vs. S
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1. A Review of General Chemistry
Electronegativity
6:09 minutesProblem 5a,b
Textbook Question
For each pair of compounds, predict which one has the higher molecular dipole moment, and explain your reasoning.
a. ethyl chloride or ethyl iodide
b. 1-bromopropane or cyclopropane
Verified step by step guidance1
Step 1: Understand the concept of molecular dipole moment. The dipole moment is a measure of the separation of positive and negative charges in a molecule. It depends on the electronegativity of atoms and the geometry of the molecule.
Step 2: Analyze the electronegativity of the halogens involved. Chlorine is more electronegative than iodine, which means it will create a larger dipole moment when bonded to carbon. Compare ethyl chloride (C2H5Cl) and ethyl iodide (C2H5I) based on this property.
Step 3: Consider the molecular geometry and bond polarity for ethyl chloride and ethyl iodide. The C-Cl bond is more polar than the C-I bond due to the higher electronegativity of chlorine, leading to a higher dipole moment for ethyl chloride.
Step 4: For 1-bromopropane (C3H7Br) and cyclopropane (C3H6), evaluate the presence of polar bonds. 1-bromopropane has a polar C-Br bond, while cyclopropane is a non-polar molecule due to its symmetrical ring structure.
Step 5: Conclude that 1-bromopropane will have a higher dipole moment than cyclopropane because it contains a polar bond, whereas cyclopropane's symmetrical structure results in no net dipole moment.
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Video duration:
6mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Molecular Dipole Moment
The molecular dipole moment is a measure of the overall polarity of a molecule, determined by the vector sum of all individual bond dipoles. It depends on both the difference in electronegativity between bonded atoms and the geometry of the molecule. A higher dipole moment indicates a more polar molecule, which affects properties like solubility and boiling point.
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Electronegativity
Electronegativity is the tendency of an atom to attract electrons in a chemical bond. In a molecule, the atom with higher electronegativity will attract shared electrons more strongly, creating a dipole. The difference in electronegativity between atoms in a bond contributes to the bond's polarity, influencing the overall dipole moment of the molecule.
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Molecular Geometry
Molecular geometry refers to the three-dimensional arrangement of atoms in a molecule. It plays a crucial role in determining the dipole moment, as the spatial orientation of polar bonds can either enhance or cancel out the overall dipole. For example, linear or symmetrical geometries may result in a net dipole moment of zero, even if individual bonds are polar.
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