Covalent Bonding + Substances

Question 1

What are the 2 types of covalent bonds?

Answer 1

• Simple Molecular
• Giant Covalent

Question 2

Definition of simple molecular structure

Answer 2

Very strong Covalent bonds between ATOMS within the molecule.
- Weak intermolecular forces between MOLECULES

Question 3

What are covalent bonds made from

Answer 3

Non-metals + non-metals

Question 4

Do simple molecular substances had high/low melting and boiling point?

Answer 4

LOW
- Weak Intermolecular forces
- require little energy to break

Question 5

What is the effect on the melting and boiling point when the relative molecular mass increases in a simple molecular substance

Answer 5

• Melting + boiling point INCREASE
• higher relative molecular mass = more intermolecular forces = more energy needed to break

Question 6

Are covalent substances conductors?

Answer 6

DO NOT CONDUCT
- no free moving charged particles
- EXCEPT GRAPHITE: has delocalised electrons that can flow

Question 7

Which 3 covalent substances have giant covalent lattice structures

Answer 7

Diamond, Silicon, Graphite

Question 8

Definition of giant covalent lattices

Answer 8

electrostatic attraction between the pairs of shared electrons and the nuclei of the bonded atoms

Question 9

Do giant covalent lattice substances have a high/low melting and boiling point?

Answer 9

VERY HIGH
- Strong covalent bond
- require a lot of energy to break

Question 10

Do giant covalent lattice structures conduct electricity?

Answer 10

DO NOT CONDUCT - not free moving charged particles
EXCEPT GRAPHITE- does have free flowing delocalised electrons

Question 11

Are giant covalent lattice structures hard or malleable?

Answer 11

Very hard, EXCPET GRAPHITE
- graphite - layers can Slide Over each other
- layers are on held by weak intermolecular forces
- graphite is soft and slippery

Question 12

what type of atom are diamond and graphite made out of

Answer 12

Carbon atoms

Question 13

Describe the properties and structure of atoms in a diamond

Answer 13

• each carbon atom covalently bonded to 4 other carbon atoms
• very strong covalent bonds: Lots of energy needed to break, very high melting point
• strong covalent bonds hold atoms in a very rigid lattice structure
• does NOT CONDUCT electricity: no free electrons/ions

Question 14

Describe the structure of atoms in graphite

Answer 14

• each carbon atom covalently bonded to 3 other carbon atoms
• creates layers of carbon atoms
• layers held weakly by intermolecular forces
• layers free to slide over eachother: soft and slippery
• used as lubricant

Question 15

Can graphite conduct electricity and why?

Answer 15

YES
- only 3 out of each carbons 4 electrons are used in bonds
- each carbon has one free delocalised electron that can move and conduct

Question 16

What is the structure of Fullerene (C60)

Answer 16

Simple molecular
Hollow sphere, made up of 60 carbon atoms

Question 17

Does fullerene have a high/low melting point?

Answer 17

LOW
- weak intermolecular forces
- needs little energy to break

Question 18

Is fullerene hard or soft?

Answer 18

Soft
- only held by intermolecular forces
- can Slide Over each other

Question 19

is fullerene a electrical conductor?

Answer 19

Poor electrical conductor
- each carbon in fullerene has one delocalised electron
- electron cant move between molecules, cant conduct well

Question 20

Why can graphite conduct electricity?

Answer 20

• only 3 out of each carbon’s 4 outer electrons are used in bonds
• each carbons has ONE electrons the is delocalised and and move freely
• graphite is a non-metal that conducts electricity

Question 21

Does graphite have a high/low melting point and why?

Answer 21

HIGH melting point
- covalent bonds in the layers need LOTS of ENERGY to break