C3 - Structure and Bonding Flashcards
What structure are giant ionic compounds arranged in?
an ionic lattice structure
What is ionic bonding?
A metal and a non-metal with opposite charges are attracted to each other due to the electrostatic force.
Three types of bonding
- ionic
- covalent
- metallic
What happens to the particles in a body when it melts?
The particles gain more energy which breaks the bonds between the particles meaning they can more freely move around.
Does the temperature increase, decrease or stay the same when a body is changing state?
The temperature stays the same. The energy being transferred from the surroundings is used to break or join the bonds between the particles in the body.
How many electrons can the first 3 shells hold?
1st : 2
2nd : 8
3rd : 8
Why are some atoms stable and some unstable?
Stable atoms have filled outer shells
Unstable atoms have incomplete outer shells
define ion
an atom with a + or - electrical charge
When can ionic compounds conduct electricity?
When they are molten. This is because the ions break free from the lattice structure and electrons are then free to move around - this means they can conduct an electrical current.
Why are most ionic compounds dissolvable in water?
A water molecule has a slight positive and negative charge so it can break apart the ionic compound.
What is covalent bonding?
Covalent bonding is when multiple non-metal atoms share electrons.
define intramolecular
strong bonds inside molecules
define intermolecular
a weaker force of attraction that acts between molecules
3 examples of giant covalent structures
- sand (SiO2)
- diamond (C)
- graphite (C)
Why are simple covalent molecules gases at room temperature?
the molecules are so small that the intermolecular forces are very weak and don’t take much energy to break.
properties of diamond
- high melting and boiling point
- crystalline shape (not lattice)
- does not conduct electricity
- very hard
- each carbon is bonded to 4 other carbons
define hardness
the measure of resistance to deformation, e.g. indentation or a scratch
properties of graphite
- electrical conductor - each carbon has a delocalised electron
- soft and slippery - layers slide off easily, used as a lubricant
- each carbon is bonded to 3 other carbons
what are fullerenes
giant covalent molecules of carbon atoms with hollow shapes. an allotrope of carbon
1 example of a fullerene
buckminsterfullerene - C60
aka buckyball
properties of fullerenes
- high tensile strength
- good electrical conductor
- good thermal conductor
what is graphene
one atom thick layer of carbon arranged in a hexagonal lattice
properties of graphene
- excellent electrical conductor
- low density
- very reactive
- strong for its mass
properties of metals
- high melting and boiling points
- good electrical conductor
- good thermal conductor
- malleable
- ductile
- sonorous
- dense
- strong
properties of giant ionic compounds
- form cubic shapes
- bad electrical conductor unless molten
- dissolves in water
- high melting and boiling points
How do metals bond?
Metallic bonding is when metals bond. They bond because there is an electrostatic attraction between the metal ions (really just the nucleus) and the sea of electrons.
define strength
how much force can be applied until a body breaks apart
Why are metallically bonded structures malleable?
The layers in the metal slide over each other when a force is applied.
define alloy
a mixture of a metal and at least 1 other element
Why are alloys stronger than pure metals?
alloys are stronger because the mixture of atoms with different radii disrupts the lattice structure causing more difficulty for layers to slide over each other
Why do nanoparticles behave differently
- they have a large surface area : volume ratio making them more reactive
- they are so small quantum mechanics govern them
