Chapter 7- Networks and Nanomaterials Flashcards
What are covalent network lattices?
Non-metals that have formed giant structures consisting of a countless number of atoms covalently bonded to one another/
What is the hardest known substance?
Diamond
What is diamond made up of?
Carbon atoms bonded together by strong covalent bonds.
What molecular shape does carbon make?
Three dimensional tetrahedral
What are some properties of covalent network lattices
- Particles held quite ridgly
- Hard and difficult to scratch
- High melting points
- Non-conductors of electricity
- Brittle
Define covalent layer lattices
Countless atoms held strongly together in planes of covalent bonds.
-present in only 2-d
What holds covalent layer lattices together?
-Weak dispersion forces
Explain the molecular structure of graphite
Layers of hexagonal rings with strong covalent bonds in two dimensions.
- only three out of the four valance electrons are being used
- The lone electron becomes de-localised and can move between layers
What is the molecular structure for bucky balls
Molecules of carbon arranged in a hollow sphere
Describe carbon nanotubes
- Continous tubes made up of flat sheets of hexagonal rings
- Essentially graphite rolled into cyclinder
- Can form a single layer, or layers of multiples
What is graphene?
A flat layer of carbon, one atom thick
- large surface area
- obtained from graphite
- conducts electricity better than any metal
Melting temperature for bucky balls
Low
