Chapter 5 Flashcards
What are the 2 major problems with Lewis theory? How are these solved?
It cannot accurately predict the 3D
shapes of molecules (Solved by VSEPR theory)
It does not account for the role of orbitals
in covalent bonding
(Solved by
Hybrid Orbital
theory and
MO theory)
Are electron pairs attracted to or repelled by each other?
Repelled
How do we predict the shape of a molecule?
Assume valence electrons are as far apart as possible
What are e- pairs also called?
e- domains
How many e- pairs do double and triple bonds count as?
1
What does e- domain geometry correspond to?
of e- domains in a lewis structure
What does molecular geometry refer to?
Position of atoms only, not bonding pairs
How do you tell the difference between trigonal planar and bent molecular geometry?
Bent has 1 lone pair, TP has all e- domains bonding
TP bond angle
120
Are nonbonding or bonding pairs larger?
Nonbonding
How does having bonding electrons affect the charge of the central atom?
Bonding electrons are shared by two
atoms, so some of the negative charge
is removed from the central atom.
How does having nonbonding electrons affect negative charge?
They’re localized
on the central atom, so the area of
negative charge takes more space.
3 Electron domains
Trigonal planar
4 Electron domains
Tetrahedral
5 Electron domains
Trigonal bipyramidal
6 Electron domains
Octahedral
1 or 2 Electron domains
Linear molecular geometry
2 bonding domains, 0 nonbonding
Linear molecular geometry
3bonding domains, 0 nonbonding
Trigonal planar molecular geometry
2 bonding domains, 1 nonbonding domain
Bent molecular geometry
Bond angle for trigonal planar
120
What do double and triple bonds do for electron density?
Make greater e- density on that side of the atom, affecting bond angles
Do more electrons in a set of bonds increase or decrease e- angles?
Increase
4 bonding domains, 0 nonbonding
Tetrahedral
3 bonding domains, 1 nonbonding domain
Trigonal pyramidal
2 bonding domains, 2 nonbonding domains
Bent
Tetrahedral bond angle
109.5
5 bonding domains, 0 nonbonding
Trigonal bipyramidal
4 bonding domains, 1 nonbonding domains
Seesaw (Lone pair makes it look like stick figure on its side with balloon head with atoms as arms and legs)
3 bonding domains, 2 nonbonding domains
T shaped (balloon man with 2 heads, 2 arms, and one leg on its side)
2 bonding domains, 3 nonbonding domains
Linear (balloon man with 2 heads and abdomen, 2 arms as atoms on its side)
Trigonal bipyramidal angles
90 and 120
6 bonding pairs, 0 nonbonding pairs
Octahedral
5 bonding domains, 1 nonbonding domains
Square pyramidal
4 bonding domains, 2 nonbonding domains
Square planar
Octahedral bonding angle
90
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Paramagnetic means it has
Unpaired electrons
Diamagnetic means it has
all e- paired
