2-Bonding, Structure And Properties Of Matter Flashcards
What r ions
Charged particles
What ions do group 2 elements form
2+ions
What ions do group 7 elements form
1- ions
What do dot and cross diagrams show
The arrangement of electrons in an atom or ion
What r the negatives of dot and cross diagrams
They don’t show the structure, size or arrangement of the compound or ion
What does a ball and stick diagram show
Shows the regular pattern of a compound and how it is arranged. With dots for the ions and lines for the bonds
What r the properties of ionic compounds
High melting and boiling points, can not conduct when solid but can when liquid
Why can ionic compounds conduct when liquid
Because the ions are free to move and carry the current
How do u work out the empirical formula of a compound
See what ions there r
Work out what the charges of the ions r
Balance the charges so the overall charge is zero
Eg potassium (K) forms 1+ ions
Oxygen (O) forms 2- ions
Needs two potassiums to balance out the oxygen
So the formula would be K2O
What different ways r they to show a covalent bond
Dot and cross diagrams, with overlapping outer shells.
Displayed formula- covalent bonds r straight lines between atoms.
3D models
Properties of simple molecular substances
Very low melting and boiling points, gases or liquids at room temperature, do not conduct electricity, b.p and m.p increase with the size of the structure
What is a polymer
A long chain of repeating units
How is the repeating unit of a polymer drawn
Brackets go round the unit with bonds coming through the sides.
An ‘n’ is put outside the bracket to show it is repeated lots of times
How many covalent bonds does each carbon atom form in diamond
4 bonds
How many bonds do each carbon atom have in graphite
3 bonds
Why can graphite conduct electricity
Because each carbon atom has a delocalised electron
Properties of graphite
Forms sheets of carbons that are not bonded together. This makes it soft and slippery.
High melting and boiling points
Conducts electricity and thermal energy
What is graphene
One layer of graphite
Properties of graphene
One atom thick.
Very strong and incredibly light
Can conduct electricity
What can fullerenes be used for
Can cage other molecules, used to deliver a drug.
Industrial catalysts- catalysts are attached to it
Strengthen materials
Why are metals malleable
Because the layers can slide over each other
Why are alloys harder than pure metals
Because the different elements distort the layers so they can’t slide over each other
What are the three states of matter
Solid
Liquid
Gas
What is the arrangement of particles in a solid
They are fixed together in a regular lattice arrangement
What is the arrangement of particles in a liquid
Randomly arranged and free to move past each other but tend to stick closely together
What is the arrangement of particles in a gas
They have no arrangement and are far apart
What is the movement like in a solid
The particles vibrate around a fixed position
What is the movement like in a liquid
Particles are constantly moving in a random directions
What is the movement like in a gas
Particles move constantly with a random motion in straight lines
What happens to particles when heated
They move more quickly causing the substance to expand
What does aqueous mean
Dissolved in water
What is the state symbol for aqueous
aq
What does the amount of energy needed to change state depend on
How strong the forces between the particles are,
The stronger the forces the more energy needed
What is the diameter of coarse particles
Between 2500nm and 10000nm
What is the diameter of fine particles
Between 100nm and 2500nm
What is the diameter of nano particles
Between 1nm and 100nm
How do u work out surface area to volume ratio
Surface area / volume
What can nano particles be used for
Catalysts
Nano-medicine
Tiny electric circuits
Cosmetics
How can silver nano particles be used
They have antibacterial properties and can be added to fibres to make surgical masks and wound dressings.
It can also be added to deodorants
What are the negative affects of using nano particles
It is unclear what medical affects they may have but they could damage cells.
They could also damage the environment when washed away
