2.1 Bonding

Question 1

2.1.2 Ionic bonding

Ionic bonding

Answer 1

• between metal and non-metal
• metals lose outer shell electrons to become positively charged ions
• Non-metals gain electrons to become negatively charged ions
• metals: group 1 and 2
• non-metals: group 6 and 7

Uses dot and cross diagram

Question 2

2.1.3 Ionic compounds

What is an ionic compound?

Answer 2

• Giant lattice structure of ions
• held together by strong electrostatic forces of attraction, between oppositely charged ions.

Question 3

2.1.4 Covalent bonding

What is covalent bonding?

Answer 3

• between non-metals and non-metals
• each element share the same number of electrons

uses dot and cross diagram

Question 4

2.1.4 Covalent bonding

Giant covalent structures: diamond

Answer 4

• 4 covalent bonds per carbon atom
• very strong covalent bonds - strong intermolecular forces
• high MP and BP - large amounts of energy needed to break bonds
• does not conduct electricity - no free electrons

Question 5

2.1.4 Covalent bonding

Giant covalent structures: Graphite

Answer 5

• 3 covalent bonds per carbon atom
• layers of hexagonal rings
• layers slide over each other (no bonds between layers) soft & slippery
• high MP to breaks bonds, strong intermolecular forces
• conducts electricity (has delocalised electrons per carbon atom)

Question 6

2.1.4 Covalent bonding

Fullerenes

Buckminsterfullerene and nanotubes

Answer 6

• carbon atoms arranged in hexagonal rings
• deliver drugs into the body
• good catalysts

Buckminsterfullerene: a hollow sphere arranged in rings
Nanotubes: a hollow shape, arranged into rings. has a high length:diameter ratio. Eg: electronics and composites

Question 7

2.1.4 Covalent bonding

Graphine

Answer 7

• one layer of graphite
• very strong, very light
• sheets of carbon atoms
• conducts electricity (has delocalised electrons)
• used to make composites

Question 8

2.1.5 Metallic bonding

Metallic bonding

Answer 8

• occurs between metals only
• strong electrostatic forces of attraction between positive ions and negative electrons
• pure metals are too soft, so often mixed with other metals to make alloys.
• alloys: distorted layers, prevents them from sliding over one another.
• harder for alloys to be bent and shaped