Bonding & Structure

Question 1

Explain the VSPER theory

Answer 1

Electron pairs repel each other to the positions of minimum repulsion which is also the position of maximum separation

Question 2

What is the shape and angle of a molecule with 2 electron pairs on the central atom?

Answer 2

Linear, 180°

Question 3

What is the shape and angle of a molecule with 3 electron pairs on the central atom?

Answer 3

Trigonal planar, 120°

Question 4

What is the shape and angle of a molecule with 4 electron pairs on the central atom?

Answer 4

Tetrahedral, 109.5°

Question 5

What is the shape and angle of a molecule with 5 electron pairs on the central atom?

Answer 5

Trigonal bipyramidal, 90° and 120°

Question 6

What is the shape and angle of a molecule with 6 electron pairs on the central atom?

Answer 6

Octahedral, 90°

Question 7

What is the shape and angle of a molecule with 3 bonded electron pairs and 1 lone pair on the central atom?

Answer 7

Trigonal pyramidal, 107°

Question 8

What is the shape and angle of a molecule with 2 bonded electron pairs and 2 lone pairs on the central atom?

Answer 8

Angular, 104.5°

Question 9

If a shape is based on tetrahedral, how much does the bond angle decrease by when there is a lone pair of electrons?

Answer 9

2.5°

Question 10

What are the 3 types of intermolecular forces? Answer in order of increasing strength

Answer 10

London forces (induced dipoles), permanent dipole/permanent dipole attractions, hydrogen bonding

Question 11

Electronegativity def

Answer 11

The ability of an element to attract the pair of electrons on a covalent bond

Question 12

Describe polar and non-polar molecules in terms of how they act in an electric field

Answer 12

Have a definite attraction from one end to the other in an electric field. Non-polar molecules will spin as both ends are negative dipoles

Question 13

How do polar molecules come about?

Answer 13

When two

Question 14

Explain how London forces arise between molecules

Answer 14

Molecules can be temporarily polarised due to instantaneous fluctuations in the UNEVEN DISTRIBUTIONS OF ELECTRONS around the nuclei. Briefly, electrons are more on one side of the molecule than the other, causing a TEMPORARY DIPOLE. As molecules move around, they cause an INDUCED DIPOLE on neighbouring molecules and attract to them.

Question 15

What is a covalent bond?

Answer 15

A strong electrostatic attraction between two nuclei and a shared pair of electrons

Question 16

How is a dative covalent bond formed?

Answer 16

A lone pair of electrons donated from one atom to the other atom which is electron deficient so it can except two electrons to complete the octet.

Question 17

Isoelectronic def

Answer 17

Different elements having the same electron configurations as each other as ions

Question 18

How do you changes in the cation affect bond strength in an ionic compound?

Answer 18

The smaller the ionic radius the stronger the attraction between ions