Chapter 16.2 Test Flashcards
What does the VSEPR theory stand for?
Valence Shell Electron Pair Repulsion Theory
What is the VSEPR theory based on?
Based on the fact that an unshared pair of electrons repel more than a single electron.
What is a VSEPR model?
A 3D representation of a molecular compound’s structure
What are the two factors to look for with respect to the VSEPR structures of molecules?
- The number of atoms bonded to the central atom
- The number of unshared pairs of electrons on the central atom
What is a tetrahedral?
A VSEPR structure with 4 atoms bonded to the central atom and no unshared pairs of electrons on the central atom.
What is a tetrahedral’s bond angle?
109.5º.
What is a pyramidal?
A VSEPR structure with 3 atoms bonded to the central atom and one unshared pair on the central atom.
What is the bond angle for a pyramidal?
107º
Why do certain VSEPR structures form different bonding angles?
The unshared pairs cause molecules to bond because they repel more and the bond angle goes down.
What is a Bent Triatomic?
A VSEPR structure with 2 atoms bonded to the central atoms and one unshared pair of electrons on the central atom.
What is the bond angle for a Bent Triatomic?
104.5º
What is a Linear Triatomic?
A VSEPR structure with 2 atoms bonded to the central atom and zero unshared pairs on the central atom
What is the bond angle for Linear Triatomic?
180º
What is a Trigonal Planar?
A VSEPR structure with 3 atoms bonded to the central atom with zero unshared pairs on the central atom
What is the bond angle of a Trigonal Planar?
120º
What are the exceptions to the Octet Rule?
Trigonal Planar and Trigonal Bipyramidal
What is a Trigonal Bipyramidal?
A VSEPR structure with 5 atoms bonded to the central atom with zero unshared pairs on the central atom.
What is a linear diatomic?
Two atoms bonded together without a central atom
What is a polar molecule’s characteristics?
It must contain polar bonds and does not have molecular symmetry.
Why must a polar molecule contain polar bonds?
They create partial charges
What is molecular symmetry?
When the same atom is bonded to all possible bonding sites, no unshared pairs of electrons may be on the central atom.
What are characteristics of a nonpolar molecule?
- has no charge
- contains nonpolar covalent bonds
- must have molecular symmetry
What does symmetry do to partial charges?
It cancels them out
What is the relationahip between diatomic molecules and types of molecules?
They have nonpolar covalent bonds and no unshared pairs and no partial or net charges, so they are nonpolar molecules.
Can nonpolar molecules contain polar covalent bonds? Why or why not?
Yes, but if they have molecular symmetry, the partial charges are cancelled and it is nonpolar.
Practice drawing VSEPR structures, Lewis structures, and assigning partial charges, net charges, write what kinds of bonds are formed, and determine if the molecule is polar or nonpolar
(Draw-use certain molecular compounds for examples.)
