Molecular Geometry and VSEPR (L2) Flashcards
What are the 3 types of interactions within a molecule
- Electrons and nuclei attract one another
- Electrons repel each other
- Nuclei repel each other
Bond length
The length of a covalent bond at which the molecule is most stable. At this distance, attractive interactions are maximised relative to repulsive interactions
Bond energy
The energy required to break the bond between atoms (kJ mol^-1). The energy increases as more electrons are shared between the atoms. The energy decreases as the bond becomes longer.
Sigma bond
Covalent bond formed by overlap of a s and/or hybrid orbitals along the bond axis
Resonance structure
Composites of equivalent lewis structures, differing only in position of electrons
VSEPR theory
Molecular shape is determined by repulsion between pairs of electrons, they will be situated as far apart as possible
VSEPR theory: 2 bonded pairs of electrons
The electron pairs are in a linear shape
VSEPR theory: 3 bonded pairs of electrons
The electron pairs are coplanar and are in the shape of a triangle
VSEPR theory: 4 bonded pairs of electrons
The electron pairs are in a tetrahedral shape
VSEPR theory: 3 bonded pairs and a lone pair
The electron pairs are in a trigonal pyramidal shape
VSEPR theory: 2 bonded pairs and 2 lone pairs
The electron pairs are in two bent shapes respectively
VSEPR theory: 5 bonded pairs
The electron pairs are in a trigonal bipyramidal shape, one axis is linear and the other is coplanar triangle
VSEPR theory: 4 bonded pairs and a lone pair
The electron pairs are in a seesaw shape with the lone pair being on the middle if the seesaw
VSEPR theory: 3 bonded pairs and 2 lone pairs
T-shaped, the bonded pairs take up the linear part of the geometry and of the other spaces
VSEPR theory: 2 bonded pairs and 3 lone pairs
The bonded pairs take up the linear part of the geometry
VSEPR theory: 6 bonded pairs
The electron pairs are in a octahedral shape, one axis is linear and the other is a plus symbol
VSEPR theory: 5 bonded pairs and a lone pair
Square pyramidal, the lone pair takes one of the linear part of the geometry
VSEPR theory: 4 bonded pairs and 2 lone pairs
Square planar, the 2 lone pairs take the linear part of the geometry
Valance bond theory
A theory which describes chemical bonding (localised bonding, hydribisation)
Can two electrons in a molecule have identical descriptions
No
What do electrons do in a molecule as they occupy it
They occupy the lowest energy orbital available
Hydridisation
When atomic orbitals are combined to create hybrid orbitals and are used for bonding
Valance bond theory
A theory which describes chemical bonding (localised bonding, hybridisation)
sp3 hybridisation
The hybridisation between a 2s and 3 2p orbitals to 4 sp3 orbitals. This can be done by taking an electron from the 2s orbital to make 3 2p orbitals which contain electrons
sp2 hybridisation
The hybridisation between a 2s and 2 2p orbitals to 3 sp3 orbitals. This can be done by taking an electron from the 2s orbital to make 2 2p orbitals which contain electrons
sp hybridisation
The hybridisation between a 2s and a 2p orbitals to 4 sp3 orbitals. This can be done by taking an electron from the 2s orbital to make a 2p orbitals which contain electrons
pi bonds
Covalent bond formed by overlap of a p orbital
What bonds are used with multiple bonds
A single sigma bond is always used and pi bonds are made around the sigma bond
