Chapter 4: Problem 71
Identify the major type of attractive force between particles of each of the following substances: a. \(\mathrm{BrF}\) b. KCl c. \(\mathrm{Cl}_{2}\) d. \(\mathrm{CH}_{4}\)
Short Answer
Expert verified
a. Dipole-dipole interaction. b. Ionic forces. c. London dispersion forces. d. London dispersion forces.
Step by step solution
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Dipole-Dipole Interactions
Dipole-dipole interactions occur between molecules that have permanent dipoles. This means the molecules have a part that is slightly positive and a part that is slightly negative due to differences in electronegativity between atoms in the molecule. For example, in bromine monofluoride (BrF), bromine and fluorine form a covalent bond but with different electronegativities. Fluorine is more electronegative and pulls the shared electrons closer, making it slightly negative and leaving bromine slightly positive. This polarity allows BrF molecules to attract each other through dipole-dipole interactions.
Understanding dipole-dipole interactions helps explain why some substances have higher boiling points or solubility in polar solvents like water.
Be sure to remember: These interactions only occur in polar molecules.
Understanding dipole-dipole interactions helps explain why some substances have higher boiling points or solubility in polar solvents like water.
Be sure to remember: These interactions only occur in polar molecules.
Ionic Forces
Ionic forces are the attractive forces that hold ions together in an ionic compound. These forces arise because of the electrostatic attraction between oppositely charged ions. In the case of potassium chloride (KCl), potassium (K) loses one electron to become a positively charged ion (K⁺), and chlorine (Cl) gains that electron to become a negatively charged ion (Cl⁻).
The resulting compound consists of these ions arranged in a lattice structure, with each positive ion surrounded by negative ions and vice versa. The strength of ionic forces contributes to the high melting and boiling points of ionic compounds.
These forces are very strong, which is why ionic substances tend to be solid at room temperature and require significant energy to melt.
The resulting compound consists of these ions arranged in a lattice structure, with each positive ion surrounded by negative ions and vice versa. The strength of ionic forces contributes to the high melting and boiling points of ionic compounds.
These forces are very strong, which is why ionic substances tend to be solid at room temperature and require significant energy to melt.
London Dispersion Forces
London dispersion forces, also known as Van der Waals forces, are a type of intermolecular force that exists between all atoms and molecules. However, they are especially significant in nonpolar molecules. These forces arise from temporary, instantaneous dipoles that occur when the electrons in a molecule or atom move around, creating momentary imbalances in the distribution of charge.
In diatomic chlorine (Cl₂), both atoms share electrons equally, making it a nonpolar molecule. The primary attractive force between Cl₂ molecules is London dispersion forces. The same applies to methane (CH₄), where the carbon and hydrogen atoms form nonpolar covalent bonds.
London dispersion forces are generally weak compared to other intermolecular forces but can become significant in larger atoms and molecules due to increased numbers of electrons.
In diatomic chlorine (Cl₂), both atoms share electrons equally, making it a nonpolar molecule. The primary attractive force between Cl₂ molecules is London dispersion forces. The same applies to methane (CH₄), where the carbon and hydrogen atoms form nonpolar covalent bonds.
London dispersion forces are generally weak compared to other intermolecular forces but can become significant in larger atoms and molecules due to increased numbers of electrons.
Nonpolar Covalent Bonds
Nonpolar covalent bonds form when two atoms share electrons equally because they have similar or identical electronegativities. This equal sharing means there is no permanent dipole in the molecule.
For instance, in methane (CH₄), the carbon and hydrogen atoms have similar electronegativities, resulting in nonpolar covalent bonds. Each hydrogen atom shares one electron with the carbon atom, leading to a stable molecule with no significant charge separation.
Likewise, in diatomic chlorine (Cl₂), the two chlorine atoms share electrons equally due to their identical electronegativity.
Nonpolar covalent bonds are common in molecules made of identical atoms or atoms with similar electronegativities. Understanding these bonds is crucial for studying molecular behavior and properties like solubility and melting points.
For instance, in methane (CH₄), the carbon and hydrogen atoms have similar electronegativities, resulting in nonpolar covalent bonds. Each hydrogen atom shares one electron with the carbon atom, leading to a stable molecule with no significant charge separation.
Likewise, in diatomic chlorine (Cl₂), the two chlorine atoms share electrons equally due to their identical electronegativity.
Nonpolar covalent bonds are common in molecules made of identical atoms or atoms with similar electronegativities. Understanding these bonds is crucial for studying molecular behavior and properties like solubility and melting points.
