Chapter 4: Problem 72
Identify the major type of attractive force between particles of each of the following substances: a. \(\mathrm{OF}_{2}\) b. \(\mathrm{MgF}_{2}\) c. \(\mathrm{NH}_{3}\) d. HCl
Short Answer
Expert verified
a. Dipole-dipole, b. Ionic bonds, c. Hydrogen bonding, d. Dipole-dipole
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 are a type of attractive force that occurs between polar molecules.
Polar molecules have regions of partial positive and partial negative charge due to uneven distribution of electrons.
In substances like \(\text{OF}_{2}\) and HCl, the molecules have permanent dipoles because of their shapes and the difference in electronegativity between their atoms.
This causes the partial positive charge of one molecule to be attracted to the partial negative charge of another.
For example, in the case of HCl, hydrogen has a partial positive charge (\(\text{δ}^{+}\)) and chlorine has a partial negative charge (\(\text{δ}^{-}\)).
The dipole-dipole interaction is then the result of the attraction between these opposite charges.
Such interactions are generally weaker than ionic or covalent bonds but stronger than van der Waals forces.
Polar molecules have regions of partial positive and partial negative charge due to uneven distribution of electrons.
In substances like \(\text{OF}_{2}\) and HCl, the molecules have permanent dipoles because of their shapes and the difference in electronegativity between their atoms.
This causes the partial positive charge of one molecule to be attracted to the partial negative charge of another.
For example, in the case of HCl, hydrogen has a partial positive charge (\(\text{δ}^{+}\)) and chlorine has a partial negative charge (\(\text{δ}^{-}\)).
The dipole-dipole interaction is then the result of the attraction between these opposite charges.
Such interactions are generally weaker than ionic or covalent bonds but stronger than van der Waals forces.
ionic bonds
Ionic bonds form between atoms that transfer electrons from one to another.
This process creates ions: one atom becomes positively charged (a cation), and the other becomes negatively charged (an anion).
In the case of \(\text{MgF}_{2}\), magnesium (Mg) loses two electrons to become \(\text{Mg}^{2+}\), while each fluorine (F) atom gains one electron to become \(\text{F}^{-}\).
The electrostatic attraction between the positively charged \(\text{Mg}^{2+}\) and the negatively charged \(\text{F}^{-}\) ions forms the ionic bond.
These bonds are very strong and result in high melting and boiling points for ionic compounds.
Ionic bonds are typically found in compounds made up of metals and nonmetals.
This process creates ions: one atom becomes positively charged (a cation), and the other becomes negatively charged (an anion).
In the case of \(\text{MgF}_{2}\), magnesium (Mg) loses two electrons to become \(\text{Mg}^{2+}\), while each fluorine (F) atom gains one electron to become \(\text{F}^{-}\).
The electrostatic attraction between the positively charged \(\text{Mg}^{2+}\) and the negatively charged \(\text{F}^{-}\) ions forms the ionic bond.
These bonds are very strong and result in high melting and boiling points for ionic compounds.
Ionic bonds are typically found in compounds made up of metals and nonmetals.
hydrogen bonding
Hydrogen bonding is a specific, strong type of dipole-dipole interaction.
This occurs when a hydrogen atom is covalently bonded to a highly electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F).
The bond forms because the hydrogen atom carries a significant partial positive charge, which strongly attracts the partial negative charge on an electronegative atom in a neighboring molecule.
For example, in \(\text{NH}_{3}\) (ammonia), the hydrogen atoms are bonded to nitrogen, creating a sizable dipole moment.
This allows the hydrogen atoms of one \(\text{NH}_{3}\) molecule to be attracted to the nitrogen atom of another \(\text{NH}_{3}\) molecule, thus forming hydrogen bonds.
Hydrogen bonds significantly influence the properties of substances, leading to higher melting and boiling points compared to similar-sized molecules without hydrogen bonds.
This occurs when a hydrogen atom is covalently bonded to a highly electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F).
The bond forms because the hydrogen atom carries a significant partial positive charge, which strongly attracts the partial negative charge on an electronegative atom in a neighboring molecule.
For example, in \(\text{NH}_{3}\) (ammonia), the hydrogen atoms are bonded to nitrogen, creating a sizable dipole moment.
This allows the hydrogen atoms of one \(\text{NH}_{3}\) molecule to be attracted to the nitrogen atom of another \(\text{NH}_{3}\) molecule, thus forming hydrogen bonds.
Hydrogen bonds significantly influence the properties of substances, leading to higher melting and boiling points compared to similar-sized molecules without hydrogen bonds.
polar molecules
Polar molecules have an uneven distribution of electron density, resulting in regions of partial positive and negative charges.
This occurs when atoms with different electronegativities form covalent bonds, causing one end of the molecule to attract more electrons.
Substances like \(\text{OF}_{2}\), \(\text{NH}_{3}\), and HCl are examples of polar molecules.
These molecules exhibit a dipole moment, which means they have a distinct positive and negative side.
The shape of the molecule also plays a critical role in its polarity.
For instance, the bent shape of \(\text{OF}_{2}\) and the trigonal pyramidal shape of \(\text{NH}_{3}\) ensure that these molecules have a net dipole moment.
These characteristics are essential in determining the type of intermolecular forces the molecules will experience, such as dipole-dipole interactions or hydrogen bonding.
This occurs when atoms with different electronegativities form covalent bonds, causing one end of the molecule to attract more electrons.
Substances like \(\text{OF}_{2}\), \(\text{NH}_{3}\), and HCl are examples of polar molecules.
These molecules exhibit a dipole moment, which means they have a distinct positive and negative side.
The shape of the molecule also plays a critical role in its polarity.
For instance, the bent shape of \(\text{OF}_{2}\) and the trigonal pyramidal shape of \(\text{NH}_{3}\) ensure that these molecules have a net dipole moment.
These characteristics are essential in determining the type of intermolecular forces the molecules will experience, such as dipole-dipole interactions or hydrogen bonding.
