C3-Structure and bonding Flashcards
what are the properties of solids
Solids - fixed shape and volume with particles in a regular arrangement - they can’t be compressed. These can vibrate constantly
what are properties of liquids
Liquids have a fixed volume but can flow and change shape - their particles have no structure but are all touching and can move past each other - they cannot be compressed
what are properties of gases
Gases have no fixed shape or volume and can be compressed easily - their particles are very spaced apart - can move at high speeds in any direction
what is the relationship between pressure and volume
Pressure and volume are inversely proportional - if you increase volume, pressure decreases and if you decrease volume, pressure increases
how does solid go from solid to gas
When heating up a solid, the particles gain kinetic energy from the thermal energy and begin to vibrate. The particles vibrate so much that they become further apart, so the density of the substance decreases and it is now a liquid. The same thing happens from liquid to gas
when heating something up why does temperature not change while change of state is happening
When heating something up, while a change of state is happening, the temperature of the substance does not increase as the thermal energy being provided is transferred into kinetic energy.
substances with a higher melting or boiling point have a stronger or weaker force/bond?
Substances with a higher MP/BP have stronger forces/bonds between their particles
define compound
A compound = two or more elements which are chemically combined
what do atoms do to get a full outer electron
To get a full outer shell, these atoms either:
1)Transfer electrons
2)Share electrons
what charge does an atom gain by gaining an electron
When an atom gains electrons it becomes negatively charged
why does an atom gain a negative charge when gaining at electron
An atom has a neutral charge, and electrons have negative charges, so when a neutral atom gains negative electrons, it also becomes negatively charged
what are the structures of ionic compounds
Ionic compounds are found in a giant ionic lattice
The very strong attractive electrostatic forces (ionic bonds) hold the ions in the lattice together very tightly
why do ionic compounds have high melting/boiling points
So, it takes a lot of energy to break a lattice, so ionic compounds have a very high MP/BP
Describe and explain if a solid ionic compound can conduct electricity:
Although it contains charged particles - the ions - they are trapped in place in the lattice by the ionic bonds. So, as they are unable to move, they can’t carry charge, so they cannot conduct electricity
Describe and explain if a molten ionic compound can conduct electricity:
When you melt an ionic compound, it releases its ions, so the ions can carry charge, so the ionic compound can conduct electricity in its molten form
Describe and explain if an aqueous ionic compound can conduct electricity:
When an ionic compound becomes an aqeous solution, its ions dissociate, so they are now free to move. As the ions can carry charge, this can conduct electricity
what does covalent bonding mean
Covalent bonding = when non-metals react and their atoms share electrons
what does molecule mean
Molecule = two or more non-metal atoms covalently bonded (the same atoms or different)
what does ionic bonding mean
strong electrostatic forces of attraction between oppositely charged ions
what produces positive charged ions
all metals
what is the hardest natural substance and what is it made of
Diamond is the hardest known natural substance –> it is made up of lots of strong covalent bonds - and each carbon makes four covalent bonds
what is the structure of diamond
Diamond is a giant covalent structure in a lattice form
what are the properties of giant covalent structures
GCS Properties:
1)very high BP/MP (reasoning = covalent bonds)
2)Insoluble in water, Except graphite, they are hard and don’t conduct electricity
what allows carbon to slip of
The weak intermolecular forces between the layers allows the layers to separate and slide off easily which is how it works in a pencil - the layers is what makes it soft
howmany bonds does each carbon make in graphite and what effect does this have
In graphite, each carbon atom makes only 3 bonds (it can make 4)
As only 3 outer electrons are taken up in a bond, one electron from each carbon atom, becomes delocalised electron. As this can move and carry charge, graphite can conduct electricity
why is graphite a good conductor of thermal energy
Graphite is also an excellent conductor of thermal energy –> the delocalised electrons move faster and rapidly transfer energy along the layers of graphite
what does INTER MOLECULAR forces mean
INTER = between MOLECULAR= molecules - forces that arise between molecules (molecules are 2 or more same or different atoms covalently bonded together)
what is Graphene
Graphene = a single layer of graphite (they discovered by sticking a piece of sellotape on graphite and pulling it off)
what are properties of graphene
4 points
A better conductor of graphite
A very low density
Most reactive form of carbon
Pieces of graphene are extremely strong for its mass
what are fullerenes
Fullerenes = large hollow cages made by C atoms joining
what are the properties of fullerenes (2 points) and what can they be used for (3points)
Properties of fullerenes:
1)high tensile strenght –> used in reinforcing composite materials like in tennis rackets
2)high electrical conductivity –> used in electrical circuits
Fullerenes can be used for:
1)drug delivery into the body
2)lubricants
3)catalysts (due to the v v high SA:V)
what are cylindrical fullerenes
Cylindrical fullerenes = carbon nanotubes –> really thin cylinders where the length is a lot bigger than the diameter
what is the structure of metals
The atoms in a metal are built up layer on top of layer in a regular pattern
SO, this means that metals can form crystals
what is galvanised steel
Galvanised steel = steel dipped into molten zinc (to prevent rusting)
what is the attraction between in metallic bonding
In metallic bonding, there is attraction between the sea of delocalised electrons and the metal cations in the middle
what are properties of metals
Properties of metals:
1)Metals are malleable (bent into shape) and they are ductile (drawn into wires) because the layers of regular, same-sized atoms slide over each other
2)Metals are very good conductors of heat AND electricity because The negatively charged delocalised electrons hold the metal cations in place by electrostatic forces of attraction
3)Metals have a high MP as it requires a lot of energy to overcome the electrostatic forces of attraction and separate the metal ions
what is an alloy
Alloys = mixtures of metals (two different metal elements OR metal and non-metal (like carbon)
what are cations and anions
Cations = positively charged ions
ANions = a Negatively charged ion
