Bonding Flashcards
what are some features of solids
1.particles in a solid are packed together in a regular pattern
2. solids have a fixed shape
in a solid, particles can vibrate but can’t move from place to place
features of liquids?
they take the shape of their container and can move from place to place
features of gases?
widely spaced
fill the space of their container
what is the process
liquid to solid
freezing
what is the process
solid to liquid
melting
what is the process
gas to liquid
condensation
why does NaCL have a high melting point
strong forces of attraction
liquid to gas
boiling
describe the limitations of the simple particle model of solid, liquids, and gases
- assumes that all particles are solid spheres
- assumed that there are no forces between the particles
what is ionic bonding
when a metal and non metal react
what type of structures do ionic compunds form
giant ionic lattice
why do ionic compounds have high melting and boiling points
strong electrostatic atttraction between oppositely charged ions requires a lot of energy to overcome
why can’t ionic compounds conduct electricity when they are solids
they have to be aqueous or molten, so ions are free to move to carrya charge and conduct electricity
what is covalent bonding
when non metals bond together
what is a covalent bond
when non metals share a pair of electrons
what is a double covalent bond
when non metals share two pair s of electrons
why do small covalent molecules have low melting and boiling points and why do they exist as gases at room temperature
.they have a strong covalent bond
. weak intermolecular forces, so doesn’t require a lot of energy to overcome
what happens to the size of a covalent molecule as the intermolecular increases
size of the molecule increases
what are the three giant covalent structures
diamond
graphite
sillicon dioxide
describe some of the features of sillicon dioxide
- sillicon and oxygen covalently bonded.
- very high melting and boiling point due to the need to break numerous strong covalent bonds.
- Always solids at room temperature.
- Tetrahedral arrangement
- semi conductor.
describe some of the features of diamond
- Each carbon atom forms covalent bonds with four other carbon atoms.
- Carbon atoms have four electrons in their outer energy level.
- Very high melting point and boiling point due to the energy required to break all covalent bonds.
- doesn’t conduct electricty because there are no delocalised electrons.
- Tetrahedral arrangement
describe some features of graphite
- Hexagonal sheets
- weak intermolecular forces because they can slide over each other.
- high melting point and boiling point
- Good conductor of both electricity and heat
- Each carbon atom is covalently bonded to three carbon atoms.
- The hexagonal rings of carbon atoms are arranged into layers.
There are no covalent bonds between the layers, which allows the layers to slide over each other. This makes graphite soft and slippery.
why can graphite conduct electricity
It has delocalised electrons within the structure and it’s bonded to three carbon atoms leaving one electron free to move to carry an electrical charge and move freely throughout the structure
why can’t diamond conduct electricity
. Each carbon atom is covalently bonded to four carbon atoms, this leaves no delocalised electrons that are free to move which are able to carry an electrical charge and move throughout the structure.
what are the allotropes of carbon
graphite
diamond
fullerenes
graphene
describe some of the properties of graphene
- Graphene is a single layer of graphite
- good conductor of electricity
- because it has delocalized electrons. These electrons can move through the graphene, carrying electrical charge.
- high melting and boiling point due to a large number of strong covalent bonds. Breaking these bonds requires a great deal of energy.
what are the uses of graphene
Useful in electronics due to its electrical conductivity.
Useful for producing new materials due to its strength.
give an example of a fullerene
buckminster fullerene
how many carbon atoms does buckminster fullerene and how is it arranged
60 carbon atoms and the atoms are arranged in a hollow sphere.
what is the use of buckminster fullerene
the space inisde buckminster fullerene is good for drug delivery into the body
what are the uses of fullerenes
Drug Delivery
Lubricants
Catalysts
what are some useful properties of nanoparticles
conduct electricity
large surface area to volume ratio
catalysts
why are polymers solids at room temperature
strong intermolecular forces of attraction between molecules, breaking these forces require a lot of energy
what are polymers ?
large molecules made from repeating monomers
why do metals conduct electricity
the delocalised electrons move through the structure of positive metal ions in the metal structure and those electrons carry a charge
describe a metallic bond
The strong electrostatic attraction between the sea of delocalized negative electrons and the positive metal ions.
what are the properties of pure metals
high melting and boiling point
malleable
conductors of heat and electricity
what is an alloy
mixture of two or more metals
why are alloys harder than pure metals
. Different atoms or elements have different sized atoms. So when another metal is mixed with a pure metal , the new element/ atoms will distort the layers of metal atoms making it more difficult for them to slide over each other.
what is the size of a nanometer
10^-9 of a metre.
what is the size of nanoparticles
1 nm to 100nm
what is the size of fine particles
100 nm to 2500 nm
what is the size of coarse particles
2500 nm and upwards
why is it that nano particles having large surface area to volume ratio is an advantage
we need less materials when using nano particles. a small amount of nanoparticles does the same job as bulk materials
what are the uses of nano science
. Medicines
Sun creams
Cosmetics
Deodorants
Electronics
Catalysts
what is an advantage of Dot and Cross Diagram
Clearly shows the origin of electrons in a molecule, distinguishing electrons from different atoms through the use of dots and crosses.
what is a limitation of a Dot and cross diagram
Fails to represent the actual shape of the molecule.
what is the limitation of a 2D stick diagrams
: 1. Does not indicate which electron in a covalent bond originates from which atom.
2. Provides no information on outer electrons that are not involved in covalent bonds.
3. Inaccurate representation of the molecule’s shape.
what is one limitation of a 3D dot and cross diagrams
Illustrates the shape of the molecule.
