Structure and bonding Flashcards
Properties of giant covalent molecules
- very high melting and boiling points
- hard and strong (graphite is soft and slippery)
- insoluble in water
- electrical insulators
Properties of graphite nanotubes
- high tensile strength (can be stretched without breaking)
- good conductors
- high melting and boiling points
- strong
Properties of buckminster fullerenes
- high melting points
- strong
- good conductors
- good lubricants - layers can slide on top of one another due to weak intermolecular forces in between layers
Properties of graphenes
- high melting and boiling points - many covalent bonds are strong and needs lots of energy to break
- good conductors of heat and electricity - each carbon atom has a free delocalised electron which can move about and carry a charge
- very strong
- transparent
- flexible
- high resistance
Uses of fullerenes
- pharmaceutical delivery
- lubricants
- catalysts
Bronze info
- made of copper and tin
- good conductor
- high strength
- corrosion resistant
Brass info
- made of copper and zinc
- malleable
- tarnish resistance
Steel info
- made of iron and carbon
- high strength
- low cost
What makes graphite slippery
its arranged in layers with weak intermolecular forces in between which allow is to slide on top one another
Properties of transition metals
- hard and strong
- high melting points
- high densities
- less reactive then alkali metals
- conductors
- form colored compounds
- can form ions with different charges
- used as catalysts
How many bonds does graphite have
3 covalent bonds
Why do most giant covalent structures not conduct electricity
all electrons are locked up in covalent bonds - no free electrons to carry a charge through the structure
Why are metals good conductors of heat and electricity
consist of delocalised electrons that are free to move and carry a current
How are metals ductile/malleable
- layers of metal ions can slide over each other
- closely packed layers (regular arrangement)
- makes them relatively soft
Uses of nanoparticles
- catalysts
- sunscreens
- deodorants
- delivering drugs around the body
How many bonds does a diamond have
4 strong covalent bonds
Why do metals have high melting and boiling points
strong electrostatic forces/metallic bonds - require lots of energy to break
Properties of gases
- can be compressed
- fill the container
- volume can change
- least dense
- particles move quickly and randomly
How do allows make metals harder and stronger
Alloys have differently sized atoms - disrupts the layers/regular structure, making it harder for them to slide on top of eachother
Sizes on nanoparticles, fine particles and coarse particles
nano: 1nm-100nm
fine: 100nm-2500nm
coarse: 2500nm-10µm
What is metallic bonding
a bond in metals
How is graphite soft
layers can slide due to weak intermolecular forces
What happens when an ionic lattice is heated
- particles vibrate vigorously
- overcome strong electrostatic forces
How are atoms arranged in a metal
- giant lattice structures
- regular pattern
- electrons in the outer shell of each atom are delocalised
- lattice of positive ions
Disadvantages of nanoparticles
- need more research
- could be absorbed into our bodies and enter our cells
- no one knows the potential long term effects
- easily released into the environment
What do nanotubes look like
- tubes of hexagonal rings of carbon
- sheets of graphite rolled up
What are alloys
mixtures of two or more elements where one is a metal
What is diamond and graphite made of
carbon
What makes graphite slippery
- arranged in layers
- no covalent bonds between the layers so they can slide
Why don’t most giant covalent structures conduct electricity
- all electrons are locked up in bonds - no free electrons to carry a charge through the structure
