General chemistryLesson 2 of 2 in the course Chemical Bonding and Molecular Geometry

VSEPR Molecular Geometry and Molecular Polarity

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

Save course
Lesson progress
0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

Lewis structures show which atoms are bonded, but they do not fully represent a molecule’s three-dimensional shape. This lesson introduces the measurements used to describe molecular structure and the basic idea behind VSEPR theory.

Bond distances are commonly reported in angstroms or picometers. One angstrom is 10−1010^{-10} meters, and one picometer is 10−1210^{-12} meters. Therefore, 100 pm=1 A˚100\ \text{pm}=1\ \text{Å}.

All flashcards

What is bond distance?
The distance between the nuclei of two bonded atoms along the line joining them; it is also called bond length.
What is a bond angle?
The angle between two bonds that share a common atom, generally expressed in degrees.
What is the central idea of VSEPR theory?
Electron-density regions around a central atom repel and tend to arrange themselves as far apart as possible.
What is the relation between angstroms and picometers?
1 A˚=100 pm1\ \text{Å}=100\ \text{pm}.
How is dipole moment related to charge separation?
Its magnitude is related to charge and separation by μ=Qr\mu=Qr, where QQ is the charge magnitude and rr is the separation.

Quiz questions

  1. What is a bond angle?Answer: The angle between two bonds that share a common atom.
  2. What electron-pair geometry corresponds to three electron-density regions around a central atom?Answer: Trigonal planar.
  3. A central atom has two bonding regions and no lone pairs. What basic geometry does VSEPR predict?Answer: Linear, with the regions directed opposite one another.
  4. Carbon dioxide has two identical polar C=O bonds arranged linearly. What is the molecule's overall polarity?Answer: It is nonpolar because the bond dipoles cancel.
  5. In a trigonal bipyramidal electron-pair geometry, where do lone pairs preferentially occupy positions?Answer: In equatorial positions, which have more room.

Based on Chemistry 2e by Paul Flowers, Klaus Theopold, Richard Langley, William R. Robinson, PhD (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

More in General chemistry

All General chemistry lessons
General chemistryCrystal Structures: Lattices, Ionic Solids, and X-Ray Diffraction5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryChemical Equations: Balancing, State Symbols, and Ionic Equations5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryOxidation Numbers and Redox Half-Reaction Balancing5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryMatter, Atomic Structure, Isotopes, and Chemical Bonding5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryStoichiometry: Balancing, Yield, Gas Relations, and Reaction Networks5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryPeriodic Trends in Atomic Size, Ionization Energy, Electron Affinity, and Metallic Character5 flashcards · 5 quiz questions · 4 gamesPlay free →