2 Bonding and structure

Question 1

Describe “ion”

Answer 1

• a charged atom
• lost or gain at least 1 electron
• can be either positive or negative
• achieving electron stability

Question 2

Describe “ionic bond”

Answer 2

Transfer of electrons between a metal and a non-metal

Question 3

Explain “ionic bond”

Answer 3

Strong electrostatic force of attraction between oppositely charged ions

Question 4

Define “isoelectronic”

Answer 4

Ions that have the same number of electrons

Question 5

Factors affecting strength of ionic bonds?

Answer 5

• ionic charge
• ionic radius

Question 6

Properties of ionic compounds?

Answer 6

• giant lattice structure
• high melting point
• conduct electricity when molten or aqueous
• hard and brittle
• only dissolve in polar solvents

Question 7

Define “electrolysis”

Answer 7

Process of breaking down a substance using electricity

Question 8

Describe “covalent bond”

Answer 8

Two atoms share at least two electrons where one electron comes from each atom

Question 9

Explain “covalent bond”

Answer 9

Strong electrostatic force of attraction between the positive nuclei and a pair of shared electrons

Question 10

Describe “dative/co-ordinate covalent bond”

Answer 10

Two atoms share two electrons, where both electrons come from the same atom

Question 11

Define “bond length”

Answer 11

The distance between the nuclei of two bonded atoms in a molecule

Question 12

Define “lone pair”

Answer 12

A pair of electrons that is not involved in bonding

Question 13

What does the VESPR theory state?

Answer 13

Lone pair-lone pair repulsion is much stronger than lone pair-bond pair repulsion and that lone pair-bond pair repulsion itself is stronger than bond pair-bond pair repulsion.

Question 14

What does VESPR lead to?

Answer 14

Maximum separation and minimum repulsion between the electron pairs

Question 15

How is a polar bond formed?

Answer 15

• molecules made up of heteroatoms
• uneven distribution of the shared pairs of electrons
• different nuclear charge of atoms
• difference in the strength of pull

Question 16

Define “electronegativity”

Answer 16

The measure of an atom’s attraction for a shared pair of electrons in a covalent bond

Question 17

Why does a polar bond arise?

Answer 17

There is an uneven distribution of electrons due to one atom is more electronegative than the other

Question 18

Factors affecting electronegativity?

Answer 18

• shielding
• atomic radius
• nuclear charge

Question 19

What makes a molecule polar?

Answer 19

The molecule has polar bonds and it is not symmetrical so the polarity doesn’t cancel out

Question 20

What are the 3 types of intermolecular forces?

Answer 20

• London dispersion forces
• permanent dipole-dipole interactions
• hydrogen bonds

Question 21

Describe “London forces”

Answer 21

• only occur between molecules made of identical atoms or atoms with similar electronegativity values
• very weak
• require very little energy to break
• strength is affected by the number of electrons

Question 22

Describe “hydrogen bonding”

Answer 22

• only applies to molecules that contain either nitrogen, oxygen or fluorine
• strongest type of intermolecular force
• molecules which show hydrogen bonding also show permanent dipole-dipole interactions

Question 23

Define “hydrogen bonding”

Answer 23

When a hydrogen atom on one molecule is attracted to more electronegative atom (specifically NOF) on a neighbouring molecule

Question 24

Define “miscible”

Answer 24

When two liquids mix together

Question 25

Define “allotropes”

Answer 25

Different forms of the same element in the same physical state

Question 26

Define “metallic bonding”

Answer 26

Strong electrostatic attraction between metal ions and the ‘sea’ of delocalised electrons

Question 27

Properties of metals?

Answer 27

• high melting and boiling temperature
• high density
• good conductor of heat and electricity
• malleable