Molecular Geometry (VSEPR) Quiz

Determine the shape:
2 ED, all bonding

Linear

Determine the shape:
3 ED, all bonding

Trigonal planar

Determine the shape:
3 ED, 1 non-bonding

Bent

Determine the shape:
4 ED, all bonding

Tetrahedral

Determine the shape:
4 ED, 1 non-bonding

Trigonal pyramidal

Determine the shape:
4 ED, 2 non-bonding

Bent

Determine the bond angle:
Linear

180

Determine the bond angle:
Trigonal planar

120

Determine the bond angle:
Bent (3 ED)

117

Determine the bond angle:
Tetrahedral

109.5

Determine the bond angle:
Trigonal pyramidal

107

Determine the bond angle:
Bent (4 ED)

105

A molecule with 2 electron domains has _____ hybridization.

sp

A molecule with 3 electron domains has _____ hybridization.

sp2

A molecule with 4 electron domains has _____ hybridization.

sp3

Shape of carbon dioxide

Linear

Shape of SO3

Trigonal planar

Shape of SO2

Bent

Shape of CH4

Tetrahedral

Shape of NH3

Trigonal pyramidal

Shape of H2O

Bent

Why is the 3D shape of molecules important?

Shape determines many properties such as reactivity, polarity, melting/boiling point, etc.

What is the basic rule for VSEPR Theory?

Electron pairs in the same shell are going to repel to be as far away from each other as possible.

What does VSEPR stand for?

Valence Shell Electron Pair Repulsion

What determines electron domain geometry?

Number of electron domains

What determines actual molecular shape?

Number of bonded atoms

How do lone pairs affect bond angles?

They decrease bond angles

What happens with electron geometry of larger molecules?

Different shapes hooked together

What determines polarity of a molecule?

Electronegativity differences

What makes a molecule polar?

If the polar bonds (dipoles) do not cancel out.

Net dipole moment

When a molecule has a positive end and a negative end

What are delocalized electrons?

electrons shared between more than one bonding position

Formation of covalent bonds often starts with excitation of atoms, which occurs when an electron is promoted from a _____ orbital to a vacant _____ orbital.

S; P

What do intermolecular forces depend on?

Size and polarity

London Dispersion Forces

Momentary dipole with momentary negative charge on one side

Which IMF holds nonpolar compounds together?

London Dispersion Forces

How do LD Forces change with increasing molecular size?

Strength increases as molecule size increases

What are dipole-dipole attractions?

Attraction between polar molecules

What are Van Der Waal's Forces

General name for LD forces and dipole-dipole attractions

What is the strongest IMF?

Hydrogen bond

IMF between polar molecules that contain hydrogen covalently bonded to a highly electronegative element

Hydrogen bond

Polarizability

How easily electron distribution can be distorted

Ion-dipole forces

Attraction between ion and polar molecule

Which type of molecule has a higher vapor pressure?

Nonpolar

Which type of molecule is more viscous with a higher surface tension?

Polar

Bromate

BrO3 (-)

Dichromate

Cr2O7 (2-)

Hydrogen carbonate

HCO3 (-)

Hydroxide

OH (-)

Thiocyanate

SCN (-)