Molecular Geometry
Molecular shapes can be predicted using the VSEPR theory
Lewis structures are two-dimensional representations of molecules
Molecules are actually three-dimensional
The shape of a molecule determines its physical and chemical properties
The structures shown in the left-hand column of Model 1 are Lewis Structures
A solid line between two element symbols represents a covalent bond
The solid lines are made up of electrons
A pair of dots represents a lone pair of electrons
The dots are also made up of electrons
"Domain" means an area within something or someone's control
Molecules with four electron domains: H2O, NH3, CH4
Molecules with two electron domains: CO2, BeF2
Molecule with three electron domains: H2CO
When determining the number of electron domains, count bonds and lone pairs on the center atom
A bonding electron domain is a bond on the central atom
A nonbonding electron domain is a lone pair on the central atom
Pairs of electrons repel each other
Two bonds on the same atom try to get as far from each other as possible
A lone pair of electrons and a bonded pair of electrons push away from each other
VSEPR theory is based on the premise that electrons around a central atom repel each other
Valence shell electrons are the most critical for determining molecular shape
Electrons around the central atom repel each other in VSEPR theory
None of the molecular shapes in Model 1 have 90° bond angles
The bond angles in three-dimensional molecules are generally larger than those in Lewis structures
Three-dimensional molecules have larger angles because electrons have an additional dimension to move away in
Molecules with four electron domains: H2O, NH3, CH4
As the number of lone pairs on the central atom increases, the bond angle decreases
Lewis structure for H2S: H - S - H
3-D drawing: Bent
Bond angle: 104.5°
Lewis structure for PH3: P - H
3-D drawing: Pyramidal
Bond angle: 107°
Lewis structure for CCl4: C - Cl
3-D drawing: Tetrahedral
Bond angle: 109.5°
Lewis structure for CS2: C = S
3-D drawing: Linear
Bond angle: 180°
Lewis structure for ozone (O3): O = O - O
Ozone has a bent shape instead of a linear shape
Ozone's bond angle is larger than that of water (H2O) because it has three electron
Molecular shapes can be predicted using the VSEPR theory
Lewis structures are two-dimensional representations of molecules
Molecules are actually three-dimensional
The shape of a molecule determines its physical and chemical properties
The structures shown in the left-hand column of Model 1 are Lewis Structures
A solid line between two element symbols represents a covalent bond
The solid lines are made up of electrons
A pair of dots represents a lone pair of electrons
The dots are also made up of electrons
"Domain" means an area within something or someone's control
Molecules with four electron domains: H2O, NH3, CH4
Molecules with two electron domains: CO2, BeF2
Molecule with three electron domains: H2CO
When determining the number of electron domains, count bonds and lone pairs on the center atom
A bonding electron domain is a bond on the central atom
A nonbonding electron domain is a lone pair on the central atom
Pairs of electrons repel each other
Two bonds on the same atom try to get as far from each other as possible
A lone pair of electrons and a bonded pair of electrons push away from each other
VSEPR theory is based on the premise that electrons around a central atom repel each other
Valence shell electrons are the most critical for determining molecular shape
Electrons around the central atom repel each other in VSEPR theory
None of the molecular shapes in Model 1 have 90° bond angles
The bond angles in three-dimensional molecules are generally larger than those in Lewis structures
Three-dimensional molecules have larger angles because electrons have an additional dimension to move away in
Molecules with four electron domains: H2O, NH3, CH4
As the number of lone pairs on the central atom increases, the bond angle decreases
Lewis structure for H2S: H - S - H
3-D drawing: Bent
Bond angle: 104.5°
Lewis structure for PH3: P - H
3-D drawing: Pyramidal
Bond angle: 107°
Lewis structure for CCl4: C - Cl
3-D drawing: Tetrahedral
Bond angle: 109.5°
Lewis structure for CS2: C = S
3-D drawing: Linear
Bond angle: 180°
Lewis structure for ozone (O3): O = O - O
Ozone has a bent shape instead of a linear shape
Ozone's bond angle is larger than that of water (H2O) because it has three electron
