Bonding

Question 1

What does ionic bonding occur in?

Answer 1

• metals and non-metals

Question 2

Describe ionic bonding

Answer 2

• metal ion loses electrons to form a full outer shell
• becomes positve (state charge here) ion
• non-metal ion gains electrons, forms full outer shell
• becomes negative (insert charge) ion
• strong electrostatic forces of attraction between opposite charges bond them together

Question 3

Describe the structure of an ionic compound

Answer 3

• giant ionic lattices
• regular structure
• strong electrostatic forces of attraction between oppositely charged ions
• forces act in all directions

Question 4

What are the properties of ionic compounds?

Answer 4

• high boiling/ melting point- large amounts of energy needed to break strong bonds
• conducts electricity when liquid, not solid- ions can’t move when solid, can move when liquid

Question 5

What does covalent bonding occur in?

Answer 5

• between non metals

Question 6

Describe covalent bonding

Answer 6

• pairs of electrons shared between atoms
• gives full outer shells

Question 6

What are the three types of molecule that can be formed by covalently bonded substances?

Answer 6

• small molecules
• very large molecules
• giant covalent structures

Question 7

What are the properties of small molecules?

Answer 7

• low melting and boiling points
• usually gases or liquids at room temp
• weak intermolecular forces (much weaker than covalent bonds)
• larger molecules = stronger intermolecular forces = higher boiling/ melting points
• do not conduct electricity (no electric charge)

Question 8

What are the properties of large molecules?

Answer 8

• high melting and boiling points
• solids at room temp.
• strong intermolecular forces between polymer molecules

Question 9

What are large molecules?

Answer 9

• polymers made by joining many monomers together
• atoms in polymer molecules linked to other atoms by strong covalent monds

polymers have very large molecules

Question 10

What are the properties of giant covalent structures?

Answer 10

• solids with very high melting points
• all atoms linked to other atoms by strong covalent bonds
• these bonds must be overcome to melt or boil these substances

Question 11

What are the properties of graphite?

Answer 11

• high melting point
• conducts electricity
• slippery (weak intermolecular forces, layers slide over each other)

Question 12

Describe graphite

Answer 12

• each carbon has 3 covalent bonds to other carbon atoms
• weak intermolecular forces between layers
• layers can slide over each other
• one delocalised electron per atom

Question 13

Describe diamond

Answer 13

• each carbon atom covalently bonded to 4 other carbon atoms
• no delocalised electrons

Question 14

What are the properties of diamond?

Answer 14

• very hard
• high melting point (high energy breaking covalent bonds)
• doesn’t conduct electricity)

Question 15

Describe graphene and its properties

Answer 15

• single layer of graphite
• conducts electricity (delocalised electrons) used for electronics
• strong covalent bonds used for composites

Question 16

Describe metallic bonding

Answer 16

• electrostatic force of attraction between positively charged centres of metal atoms and delocalised electrons
• electrons can move through structure
• metals = giant structures of atoms arranged in a regular pattern

Question 17

What are the properties of metals?

Answer 17

• high melting and boiling points (giant structure of strong metallic bonding)
• can be bent or shaped- pure metals = atoms arranged in layers, can slide over each other
• good electrical conductors - delocalised electrons carry electrical charge through structure of metal
• good thermal conductors - energy transferred by delocalised electrons

Question 18

What are the properties of alloys?

Answer 18

• harder than pure metals- distorted layer structure
• harder to slide over each other