C2 Bonding, structures and states of matter Flashcards
what are the properties of solids
particles are in a fixed shape, state symbol (s), fixed shape and volume
what are the properties of liquids
state symbol (l), changes shape in different containers, particles can flow over eachother but are still attracted to eachother.
what are the properties of gases
state symbol (g), particles are free to move, can be easily compressed, expands to fill shape of container
what is the state symbol (aq)
aqueous, something dissolved in water
what is the process from solid to gas
sublimation
what is the process from gas to solid
deposition
what are the limitations of the particle model?
The simple particle model assumes that particles are solid spheres.
In most substances the particles are atoms, molecules or ions, and not solid spheres.
Atoms, molecules or ions vary in size - in particle theory they are represented as equal in size.
Particle theory diagrams do not show that there are forces or bonds between the particles.
Atoms are mostly empty space so real particles are not solid at all!
what are the two types of atoms?
metal and non metal
what do metals do when forming an ion?
metals loose elctrons when froming ions, they form postitive ions
what do non metals do when forming ions?
non metals gain electrons when forming ions, they form negative ions
how are ionic bonds formed?
ionic bonds are formed with electrostatic attraction
what is the elctrostatic attraction between?
opposite charges, positive metal ions and negative non metal ions
how do you work out ionic formulae?
switch the charges of the opposite elements to make it neutral.
what do electrostartic attractions hold?
they hold oppositley charged ions in a lattice
when are covalent bonds formed?
Covalent bonds are formed when atoms of non-metals share pairs of electrons with each other
each shared pair of electrons is a covalent bond
for covalent bonding you only show the ……… shell
outer
Explain the bonding in lithium fluoride
Lithium fluoride is an ionic compound.
A lithium atom loses one electron to make a Li+ ion.
This electron is transferred to fluorine to make a F- ion.
The atoms are held in place by electrostatic attraction between the positive and negative ions,
In a lattice.
what do giant ionic lattices have?
Strong electrostatic forces of attraction between oppositely charged ions
So have very high melting and boiling points
Lots of heat energy needed to overcome strong electrostatic forces of attraction
what are molten ionic compounds?
Cannot conduct electricity when solid - ions are in fixed positions
When molten the electrostatic attraction has been overcome
Ions able to move and carry the charge
what are ionic compound solutions?
Ions separate and interact with water molecules
Ions are free to move and carry the charge
What makes copper a good material for a wire?
Good conductor of electricity
Malleable - able to be hammered or pressed into shape without breaking or cracking.
Ductile - able to be drawn out into a thin wire.
what is metallic bonding?
2 or more metal atoms, giant structure of atoms, delocalised electrons free to move throughout structure, delocalised electrons carry current, positive metal ions, malleable layers can slide over each other
Explain why metals conduct electricity
the atoms are arranged in a giant structure, delocalised electrons are free to move throughout the whole structure.
what is an alloy?
An alloy is a mixture which contains at least one metal.
what is the difference between a metal and an alloy?
metal:
atoms can slide
same size
softer
alloy:
atoms different sizes
layers cant slide
stronger and more brittle
suggest why conductivity increases across the periodic table from sodium to magnesium to aluminium (4)
from left to right across the period, atoms of elements have more free electrons, because they have more electrons in the outer shell
what are the properties of diamond?
Each C atom is covalently bonded to 4 other C atoms
Bonds are strong
Large number of bonds
High melting point and very hard - difficult to break the strong bonds
Cannot conduct electricity
Uses: cutting tools, e.g. drill bits
explain why diamond has a high melting point?
there are large numbers of covalent bonds, between atoms, the covalent bonds are strong
what are the properties of graphite?
Each C atom is covalently bonded to 3 other C atoms
One unpaired electron which is free to move between layers
Weak intermolecular forces between layers - soft as layers slide
Large number of bonds
High MP - difficult to break the strong bonds
Can conduct electricity due to free electron movement throughout structure
Uses: pencil (layers slide), lubricant, electrodes
why can graphite be used in the leads of pencils?
because graphite is made of layers of carbon atoms, that have weak forces of attraction between layers, so the layers can slide off each other and the layers can peel off
why can graphite be used as an electrical conductor?
each carbon atom has 3 covalent bonds, which means there are free electrons to move
what are the features of graphene?
one atom thick, thin and flexible, 3 covalent bonds per atom of carbon, each atom has one unpaired, delocalised electron so good conductor of electricity, giant structure, strong covalent bonds, high melting point, light weight
what are the uses of graphene?
electronic screens,
what are the features of spherical fulurene?
covalent bonds, 3 carbon bonds for each atom, weak inter molecular forces between spheres, high tensile strength, large structure, does not conduct electricity, electrons do not move out, high melting point.
what are the uses of spherical fulurene?
pharmaceutical delivery in the body
lubricants in machines to stop moving parts grind together
catalyst speed up chemical reactions
what are the features of cylindrical fulurene?
nano tubes, hollow, strong many covalent bonds, does conduct electricity because of delocalised electrons, strong, high tensile strength (can be stretched without breaking)
what are the uses of cylindrical fulurene?
deliver drugs and electronics, tennis rechets
why does graphene conduct electricity?
each carbon atoms has an unpaired electron, the electrons are delocalised
why would graphene would not be suitable for a touch screen?
the layers would slide
how many carbon atoms does buckminstersfullurne have
60
