C3: Structure and Bonding Flashcards
Solids:
-fixed shape and volume, cannot be compressed, vibrate in fixed positions.
Liquids:
-fixed volume, can flow, more space than when solid.
-particles slide over one another.
Gases:
-no fixed shape or volume, compressed easily
-random and rapid movements.
What does particle theory describe?
-movement of particles
-average distance between particles
Liquid to solid
freezing
solid to liquid
melting
liquid to gas
evaporation
gas to liquid
condensation
solid to gas
sublimation
gas to solid
depostion
Why doesn’t the temperature increase when changing state?
All energy is going towards breaking the particles apart from one another.
What are the limitations of the particle model?
-No electrostatic attractions
-Solid spheres, not atoms
What is the bonding that shares electrons?
Covalent
What is the bonding that transfers electrons?
Ionic
What charge ions do metals form?
Positive
What charge ion do non-metals form?
Negative
What do we use to represent ionic bonding?
dot and cross diagrams
What charge ion do group 5 form?
3-
What charge ion do group 4 create
Don’t make ions silly (other than tin and lead)
How are ionic compounds held together?
Strong forces of attraction between oppositely charged ions.
What can ionic bonds create (if there are lots of them)
-giant ionic structures
-giant ionic lattices
What is a lattice?
arranged in a regular pattern
main property of ionic compounds?
high melting and boiling points
why can molten ionic COMPOUND then conduct electricity when dissolved in water?
Attracted to oppositely charged electrodes and carry their electrical charge through the liquid.
why can ionic compound IN SOLUTION conduct electricity?
ions (+delocalised electrons) can move around freely within the solution.
Covalent bonding - what is it between?
non metal and non metal
what does covalent bonding entail?
two non metals sharing electrons to fill their outer shells.
What are giant covalent structures also known as?
Macromolecules
What is diamond an example of?
Giant covalent structure
What is diamond made of
Carbon atoms forming four covalent bonds with its neighbours.
How do we express covalent bonds?
Dot and cross (but with circles!)
Intermolecular forces _____ with the size of the molecules.
Increase (higher b+m points but thats easy.)
What is a polymer
made up of many small reactive molecules that bond to each other to form long chains.
example of polymer
poly(ethene)
Long polymers can be expressed like:
( H H )
-(-C—-C-)- (poly(ethene))
( H H ) n
Can compounds made of simple molecules conduct electricity?
NO, no overall charge, neutral molecules can’t carry charge.
Properties of diamond
-very hard
-high boiling point
-insoluble in water.
can giant covalent structures conduct?
NO, other than GRAPHITE
Why can graphite conduct electricity?
It has layers, and delocalised electrons run between the layers.
What do the layers in graphite form?
hexagons
What is graphite arranged in?
layers
why is graphite soft and slippery?
it’s in layers
what is a fullerene?
hollow-shaped molecules of carbon
Shape of fullerenes:
hexagon
Example of a fullerene:
carbon nanotube
Properties of fullerenes:
-high tensile strength
-high electrical and thermal conductivity.
What can fullerenes be used for?
drug delivery into the body.
What is graphene?
a single sheet of carbon atoms from graphite
How thick is graphene?
1 atom thick.
Properties of graphene?
-excellent conductor of thermal energy and electricity.
-low density
-strong
Metals can form what, even though not visible to the naked eye?
crystals
What is metallic bonding between?
two metals
How do the outer electrons move in metallic bonding?
Move freely throughout the structure (delocalised)
What do the delocalised electrons in metallic bonding do?
Make them conduct electricity.
What is an alloy?
mixture of two or more elements, at least one of which is a metal.
Why are metals used as cooking utensils?
Cook conductors of thermal energy, high melting points.
Why do metals have high melting points?
giant structures, lots of energy to break apart electrostatic attraction.
1nm=?m
1x10 (-9) m
What do nanoparticles have that makes them useful?
high surface area :volume
uses of nanoparticles (materials):
-glass (breaks down dirt)
-Sunscreen (effective blockers)
-cosmetics (deeper into skin)
uses of nanoparticles (medical)
-nanocages delivering drugs
-can potentially change the proteins in a cancer cell and destroy it.
risks of nanoparticles:
-can cause explosion of catalysts
-finding way into atmosphere, can breathe in and damage lungs.
-affect wildlife
