bonding ✓

Question 1

how does covalent bonding happen ?

Answer 1

• two non-metals
• they cannot give or take electrons so they SHARE their electrons
• this creates an ion

Question 2

how does ionic bonding happen ?

Answer 2

• happens between metals and non metals
• metals want to lose electrons and non-metals want to gain them
• this creates two ions

Question 3

what does the acronym OILRIG mean ?

Answer 3

Oxidation
Is
Loss (of electrons)
Reduction
Is
Gain (of electrons)

Question 4

if when formed the ion has lost (2) electrons what is its charge ?

Answer 4

(2) +

Question 5

if when formed the ion has gained (2) electrons what is its charge ?

Answer 5

(2) -

Question 6

how to work out a formula for the compounds formed if they balance eg Li+ and F- ?

Answer 6

LiF

Question 7

how to work out a formula for the compounds formed if they don’t balance eg Li+ and F2- ?

Answer 7

• both both go into 2
• times the Li+ by 2 and times the F2- by 1
• this makes Li2F

Question 8

how to define and ionic bond ?

Answer 8

• the string electrostatic attraction between oppositely charged ions

Question 9

why do giant ionic lattices have high melting and boiling points ?

Answer 9

• the electrostatic attraction between the oppositely charged ions its very strong
• takes a large amount of energy to pull them apart
• so they have a high melting and boiling point

Question 10

why do ionic substances conduct electricity only when they are molten or dissolved (aqueous) ?

Answer 10

• ionic substances do not have electrons that can move but they do have ions
• the problem is that in a lattice these are unable to move
• however if the substance is made molten the ions can move
• also is the substance is aqueous then the ions can move

Question 11

how to define a covalent bond ?

Answer 11

• electrostatic attraction between a pair of shared electrons and the nuclei of the atoms

Question 12

why do simple covalent structures have a low melting and boiling and are unable to conduct electricity ?

Answer 12

• they have low melting and boiling points because the force in the molecules are weaker
• they cannot conduct electricity because they have no free moving electron or ion

Question 13

what is the trend between boiling point and the length of the molecule ?

Answer 13

the longer the molecule the boiling points it has

Question 14

what is the structure of diamond and graphite ?

Answer 14

giant covalent structures

Question 15

what are the properties of diamond ?

Answer 15

• made up of carbon
• each carbon atom in a diamond has four bonds
• these are all strong and covalent
• there are lots of bonds so lots of energy is needed to break them
• so it has a high melting and boiling point
• they are strong because any pressure applied spreads out around the structure
• they are brittle (do not like being knocked)

Question 16

what are the properties of graphite ?

Answer 16

• made up of carbon
• each carbon atom in graphite has 3 bonds
• they form a planar (flat) hexagonal structure
• the layers are able to slide over each other
• makes them useful in industry as a solid lubricant
• has high melting and boiling points it is made up of lots of strong covalent bonds that require large amounts of energy to break them
• has a lower melting and boiling point that diamond

Question 17

what is a very common question when talking about the melting and boiling points of molecules, eg AlF3 and SrBr2 ?

Answer 17

• AlF3 has 3+ and 3- charges
• SrBr2 has 2+ and 2- charges
• AlF3 therefore has a stronger electrostatic attraction
• this means that more energy is needed to break the AlF3 bonds
• therefore AlF3 has higher melting and boiling points