Podcast
Questions and Answers
In a polar covalent bond, the shift of electrons is towards the atom with:
In a polar covalent bond, the shift of electrons is towards the atom with:
What type of bond results from unequal sharing of electrons?
What type of bond results from unequal sharing of electrons?
Which type of bond involves the sharing of electrons in a way that results in a separation of electric charge?
Which type of bond involves the sharing of electrons in a way that results in a separation of electric charge?
A coordinate covalent bond forms when:
A coordinate covalent bond forms when:
Signup and view all the answers
What characteristic of a molecule leads to the formation of polar covalent bonds?
What characteristic of a molecule leads to the formation of polar covalent bonds?
Signup and view all the answers
Which chemical property influences the dominance of dispersion forces in a molecule?
Which chemical property influences the dominance of dispersion forces in a molecule?
Signup and view all the answers
What is the term used to describe the ease with which a dipole can be induced in an atom or molecule?
What is the term used to describe the ease with which a dipole can be induced in an atom or molecule?
Signup and view all the answers
Which type of dipole exists in all polar molecules due to the difference in electronegativity values of bonded atoms?
Which type of dipole exists in all polar molecules due to the difference in electronegativity values of bonded atoms?
Signup and view all the answers
In a polar substance, how do molecules align in relation to dipoles?
In a polar substance, how do molecules align in relation to dipoles?
Signup and view all the answers
Which type of dipole is created temporarily due to the influence of a neighboring dipole?
Which type of dipole is created temporarily due to the influence of a neighboring dipole?
Signup and view all the answers
What dominates the properties of higher molecular weight alcohols in terms of determining solubility?
What dominates the properties of higher molecular weight alcohols in terms of determining solubility?
Signup and view all the answers
Why does ethanol (C4H9OH) have higher O-H bond dipole moment compared to n-pentane (C5H12)?
Why does ethanol (C4H9OH) have higher O-H bond dipole moment compared to n-pentane (C5H12)?
Signup and view all the answers
What is the term for the intermolecular force of attraction resulting from the displacement of electrons and the formation of an instantaneous dipole?
What is the term for the intermolecular force of attraction resulting from the displacement of electrons and the formation of an instantaneous dipole?
Signup and view all the answers
Which type of attraction involves the ease with which electron charge density is distorted by an external electric field?
Which type of attraction involves the ease with which electron charge density is distorted by an external electric field?
Signup and view all the answers
Which process involves the displacement of electrons in a nonpolar species to form an instantaneous dipole, followed by the induction of a dipole in a neighboring atom or molecule?
Which process involves the displacement of electrons in a nonpolar species to form an instantaneous dipole, followed by the induction of a dipole in a neighboring atom or molecule?
Signup and view all the answers
What term describes the attraction between two molecules due to an instantaneous dipole in one molecule inducing a dipole in another molecule?
What term describes the attraction between two molecules due to an instantaneous dipole in one molecule inducing a dipole in another molecule?
Signup and view all the answers
Which statement accurately describes dispersion forces?
Which statement accurately describes dispersion forces?
Signup and view all the answers
What property determines the strength of dispersion forces between molecules?
What property determines the strength of dispersion forces between molecules?
Signup and view all the answers
Study Notes
Polar Covalent Bond
- A polar covalent bond is a separation of electric charge in a covalent bond, involving a shift of electrons toward the atom with the more negative electron affinity.
- This bond results from unequal sharing of electrons due to differences in electronegativity values of the two atoms.
- Example: H+ → Cl-
Polar Molecules
- Water is a polar molecule, with covalent bonds between hydrogen and oxygen atoms being polar covalent bonds.
- The shared electrons spend more time near the oxygen nucleus, giving it a small negative charge, and near the hydrogen nuclei, giving them small positive charges.
Coordinate Covalent Bond
- A coordinate covalent bond is formed when the lone or non-bonding pairs of electrons in an atom take part in a form of bonding.
- The two electrons being shared by the two atoms are supplied by only one of the participating atoms.
- The atom accepting the electron must have an empty orbital to accommodate the two electrons.
- Example: The bond between ammonia (NH3) and hydrogen ion (H+) to give ammonium (NH4+).
Polarizability
- Polarizability is the ease with which a dipole can be induced in an atom or molecule.
- Polarizability increases with an increased number of electrons in a species.
Dipole-Dipole Interactions
- Permanent dipole: exists in all polar molecules due to differences in electronegativity values of bonded atoms.
- Instantaneous dipole: temporary dipole that exists as a result of fluctuation in the electron cloud.
- Induced dipole: temporary dipole created due to the influence of a neighboring dipole (permanent or instantaneous).
Dipole-Dipole Attractions
- In a polar substance, molecules try to line up with the positive end of one dipole directed toward the negative ends of neighboring dipoles.
- This additional partial ordering of molecules causes a substance to persist as a solid or liquid at temperatures higher than otherwise expected.
- Example: Ethanol and n-pentane, with different molecular masses, but differing O-H bond dipole moments and C-H bond dipole moments.
Van der Waals Forces
- Van der Waals forces result from fluctuations in charge density of particles.
- Examples of van der Waals forces include hydrogen bonding, dispersion forces, and dipole-dipole interactions.
- Properties of Van der Waals forces:
- They are weaker than either ionic or covalent chemical bonds.
- They are not directional.
- They act only over a very short range.
- The interaction is greater when molecules draw closer.
- They are independent of temperature, with the exception of dipole-dipole interactions.
Instantaneous and Induced Dipoles
- The displacement of electrons causes a normally non-polar species to become polar, forming an instantaneous dipole.
- Following this, electrons in a neighboring atom or molecule may be displaced, also producing a dipole, called an induced dipole.
- These two events lead to an intermolecular force of attraction called an instantaneous dipole-induced dipole attraction or dispersion force or London force.
- Dispersion forces exist between all molecules and are much weaker than covalent bonds within molecules.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn about polarizability, dipole-dipole interactions, permanent dipoles, instantaneous dipoles, and induced dipoles in atoms and molecules. Understand how the ease of inducing a dipole is related to polarizability and electron distribution.
