Ch - 3 (Giant Structures & Metallic Bonding ) Flashcards
1
Q
What are the examples of giant covalent structures?
A
- Diamond
- Graphite
2
Q
What is the structure of a diamond?
A
- Each carbon atom bonds with 4 other carbon atoms
- Forms tetrahedron
- Very strong
- No intermolecular forces
3
Q
What is the structure of graphite?
A
- Each carbon atom is bonded to 3 other carbon atoms
- Forms layers of hexagon
- Weak intermolecular foxes.
4
Q
Properties of diamond?
A
- Doesn’t conduct electricity (No free charged ion)
- High m.p. (Strong covalent bonds, needs more energy)
- Extremely hard and dense
5
Q
What is the use of diamond?
A
- Jewellery
- cutting tools
6
Q
Properties of graphite?
A
- Weak intermolecular forces that makes layers slide and slippery
- conducts electricity
- High m.p.
- less dense than diamond.
7
Q
What are the uses of graphite?
A
- Pencils
- Industrial lubricants
- Used for electrodes and electrolysis.
8
Q
How is the structure of silicon dioxide?
A
- Macromolecular (Sand and quartz)
- Each oxygen covalently bonds with 2 silicon atoms
- Each silicon atom covalently bonds with 4 oxygen atoms
- Tetrahedron
9
Q
What are the properties of silicon dioxide?
A
- No intermolecular forces so same property as diamond.
- Hard
- High b.p.
- Insoluble in water
- Does not conduct electricity
- Cheap (Sandpaper)
10
Q
What is metallic bonding?
A
Metal bonds are held together in a giant metallic lattice
11
Q
What happens to the atoms of metallic bonding?
A
- Lose electrons from outer shell and become positively charged ions.
- Delocalised electrons
12
Q
How do the electrons flow?
A
Like a ‘sea of electrons’
13
Q
What are the properties of metals?
A
- High m.p. & b.p.
- Conduct electricity
- Malleable and ductile
14
Q
Why do metals have High m.p. & b.p.?
A
- Strong metallic bonding between positive ions and delocalised electrons
- Lot of heat required
15
Q
Why do metals conduct electricity?
A
- Delocalised electrons
