Molecular Geometry and VSEPR (L2)

Question 1

What are the 3 types of interactions within a molecule

Answer 1

1. Electrons and nuclei attract one another
2. Electrons repel each other
3. Nuclei repel each other

Question 2

Bond length

Answer 2

The length of a covalent bond at which the molecule is most stable. At this distance, attractive interactions are maximised relative to repulsive interactions

Question 3

Bond energy

Answer 3

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.

Question 4

Sigma bond

Answer 4

Covalent bond formed by overlap of a s and/or hybrid orbitals along the bond axis

Question 5

Resonance structure

Answer 5

Composites of equivalent lewis structures, differing only in position of electrons

Question 6

VSEPR theory

Answer 6

Molecular shape is determined by repulsion between pairs of electrons, they will be situated as far apart as possible

Question 7

VSEPR theory: 2 bonded pairs of electrons

Answer 7

The electron pairs are in a linear shape

Question 8

VSEPR theory: 3 bonded pairs of electrons

Answer 8

The electron pairs are coplanar and are in the shape of a triangle

Question 9

VSEPR theory: 4 bonded pairs of electrons

Answer 9

The electron pairs are in a tetrahedral shape

Question 10

VSEPR theory: 3 bonded pairs and a lone pair

Answer 10

The electron pairs are in a trigonal pyramidal shape

Question 11

VSEPR theory: 2 bonded pairs and 2 lone pairs

Answer 11

The electron pairs are in two bent shapes respectively

Question 12

VSEPR theory: 5 bonded pairs

Answer 12

The electron pairs are in a trigonal bipyramidal shape, one axis is linear and the other is coplanar triangle

Question 13

VSEPR theory: 4 bonded pairs and a lone pair

Answer 13

The electron pairs are in a seesaw shape with the lone pair being on the middle if the seesaw

Question 14

VSEPR theory: 3 bonded pairs and 2 lone pairs

Answer 14

T-shaped, the bonded pairs take up the linear part of the geometry and of the other spaces

Question 15

VSEPR theory: 2 bonded pairs and 3 lone pairs

Answer 15

The bonded pairs take up the linear part of the geometry

Question 16

VSEPR theory: 6 bonded pairs

Answer 16

The electron pairs are in a octahedral shape, one axis is linear and the other is a plus symbol

Question 17

VSEPR theory: 5 bonded pairs and a lone pair

Answer 17

Square pyramidal, the lone pair takes one of the linear part of the geometry

Question 18

VSEPR theory: 4 bonded pairs and 2 lone pairs

Answer 18

Square planar, the 2 lone pairs take the linear part of the geometry

Question 19

Valance bond theory

Answer 19

A theory which describes chemical bonding (localised bonding, hydribisation)

Question 20

Can two electrons in a molecule have identical descriptions

Answer 20

No

Question 21

What do electrons do in a molecule as they occupy it

Answer 21

They occupy the lowest energy orbital available

Question 22

Hydridisation

Answer 22

When atomic orbitals are combined to create hybrid orbitals and are used for bonding

Question 23

Valance bond theory

Answer 23

A theory which describes chemical bonding (localised bonding, hybridisation)

Question 24

sp3 hybridisation

Answer 24

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

Question 25

sp2 hybridisation

Answer 25

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

Question 26

sp hybridisation

Answer 26

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

Question 27

pi bonds

Answer 27

Covalent bond formed by overlap of a p orbital

Question 28

What bonds are used with multiple bonds

Answer 28

A single sigma bond is always used and pi bonds are made around the sigma bond