Chapter 9 Review Flashcards
What parts of a molecule define the shape and size of the molecule?
The bond angles and bond lengths
What determines the properties of a substance?
The shape of the molecule, the size of the molecule, the strength of its bonds, and the polarity of the bonds
Electron domains are . . .
regions where electrons are likely to be found around an atom
What is considered as ONE electron domain?
a single bond, a double bond, a triple bond, and a lone pair
The BEST arrangement of a given number of electron domains is the one that . . .
minimizes the repulsions among them
Molecular Geometry is . . .
the arrangement of only the bonded atoms in a molecule or ion
Molecular Geometry describes . . .
the shape of only those electron domains that contain bonding electrons
Determine Molecular Geometry by . . .
counting the number of bonding domains
2 electron domains, 0 nonbonding domains
linear
3 electron domains, 0 nonbonding domains
Trigonal Planar
3 electron domains, 1 nonbonding domain
Bent
4 electron domains, 0 nonbonding domains
Tetrahedral
4 electron domains, 1 nonbonding domain
Trigonal Pyramidal
4 electron domains, 2 nonbonding domains
Bent
5 electron domains, 0 nonbinding domains
Trigonal Bipyramidal
5 electron domains, 1 nonbonding domain
Seesaw
5 electron domains, 2 nonbonding domains
T-Shaped
5 electron domains, 3 nonbonding domains
Linear
6 electron domains, 0 nonbonding domains
Octahedral
6 electron domains, 1 nonbinding domain
Square Pyramidal
6 electron domains, 2 nonbonding domains
Square Planar
Nonbonding electron pairs are . . . than bonding pairs
physically larger
Because nonbonding electron pairs are physically larger than bonding pairs, they . . .
have greater repulsions
Nonbonding pairs tend to . . .
decrease angles in a molecule
Double and triple bonds place . . . than do single bonds
greater electron density on one side of the central atom
Linear EDG molecules have a predicted angle of . . .
180 degrees
Trigonal Planar EDG molecules have a predicted angle of . . .
120 degrees
Tetrahedral EDG molecules have a predicted angle of . . .
109.5 degrees
Trigonal Bipyramidal EDG molecules have a predicted angle of . . .
90 degrees (from vertical bonds to horizontal bonds) and 120 degrees (between horizontal bonds)
In a Trigonal Bypyramidal EDG, lone electron pairs prefer to be in . . .
equatorial positions rather than axial positions
Octahedral EDG molecules have a predicted angle of . . .
90 degrees and (between lone electron pairs) 180 degrees
In Octahedral EDG molecules, lone electron pairs are placed . . .
opposite of each other
In larger molecules, there is more than one . . .
central atom
If electrons are shared unequally, bonds become . . .
polar
A molecule is polar (or nonpolar) depending on whether or not . . .
the dipoles “combine” or “cancel each other”
To determine if a molecule is polar or not, you must consider these two things
- the polarity of each bond
- Geometry of the molecule
Polar molecules result from . . .
a distribution of charge from polar bonds that is not symmetrical
The dipoles of polar molecules . . .
combine
The dipoles of nonpolar molecules . . .
cancel each other
First step to determine molecule polarity
Draw Lewis structure
Second step to determine molecule polarity
Determine if the bonds are polar or nonpolar
Third step to determine molecule polarity
Identify EDG
Fourth step to determine molecule polarity
Identify MG
Final step to determine molecule polarity
Determine if there is an asymmetry to the molecule
Valence Bond (VB) Theory assumes . . .
a covalent bond is formed between two atoms by the overlap of half-filled valence atomic orbitals
When atomic orbitals mix to form new orbitals, what are these orbitals called?
Hybrid orbitals
Hybrid orbitals are degenerate. In other words, they are . . .
equivalent in energy
The number of hybrid orbitals is equal to the number of . . .
atomic orbitals
An atomic s + p orbital results in . . .
2 sp hybrid orbitals
An atomic s + p + p orbital results in . . .
3 sp^2 hybrid orbitals
An atomic s + p + p + p orbital results in . . .
4 sp^3 hybrid orbitals
The number of hybrid orbitals is . . . the number of electron domains around a central atom
equal to
