C2 - Covalent Bonding (PAPER 1) Flashcards
How are covalent bonds formed
By atoms sharing electrons
Which type of atoms form covalent bonds between them
non-metals
Describe the structure and bonding of a giant covalent substance
billions of atoms bonded together by strong covalent bonds
Describe the structure and bonding of small molecules
- small numbers of atoms grouped together into molecules
- strong covalent bonds between the atoms
- weak intermolecular forces between molecules
Describe the structure and bonding of polymers
- many identical molecules joined together with strong covalent bonds in a long chain
- weak intermolecular forces between chains
why do giant covalent structures have high melting points
lots of energy is required to break the strong covalent bonds between atoms
why do small molecules have low melting points
only a small amount of energy is required to break the weak intermolecular forces
Why do large molecules have higher melting points than small molecules
the intermolecular forces are stronger in larger molecules
why do covalent substances not conduct electricity
no delocalised electrons or ions
Describe the structure and bonding in graphite
- each carbon atom is bonded to three others in hexagonal rings arranged in layers
- there are delocalised electrons and weak forces between layers
Why can graphite conduct electricity
delocalised electrons can move through the graphite
why is graphite soft
layers are not bonded so they can slide over each other
what is graphene
a single layer of graphite
what are two properties of graphene
strong, conductor of electricity
what is a fullerene
hollow cage of carbon atoms arranged as a sphere or a tube
