3. Structure and Bonding Flashcards
The three states of matter are…
solids, liquids and gases
Particles in a solid are…
packed closely together and vibrate around fixed positions
Particles in a liquid are…
close together but can slide over each other with random motion
Particles in a gas have…
lots of space between them and move around quickly and randomly
In melting and boiling…
energy is transferred from the surroundings into the substance
In freezing and condensing
energy is transferred from the substance into the surroundings
Elements in group 1 can react with…
elements in group 7
Group 1 atoms can lose…
1 electron to become stable
Group 7 atoms can gain…
1 electron to become stable
Ionic compounds are held together by…
strong forces of attraction between their oppositely charged ions, this is ionic bonding
Elements than can form ionic compounds are found in…
groups 1, 2, 6 and 7
A giant ionic lattice is held together because…
it takes a lot of energy to break many strong ionic bonds that operate in many directions
Why do ionic compounds only conduct electricity when molten or dissolved in water?
Their ions can then become mobile and carry charge throughout the liquid
When are covalent bonds formed?
When atoms of non-metals share pairs of electrons with eachother
Each shared pair of electrons is…
a covalent bond
Substances containing covalent bonds consist of simple molecules yet some have…
giant covalent structures
Substances made of simple molecules have…
low melting and boiling points
Simple molecules cannot carry electrical charge because…
they have no overall charge
Forces between simple molecules are…
weak
Giant covalent structures have very high…
melting and boiling points
Graphite is soft and slippery as…
It contains layers of covalently bonded carbon atoms yet there are no covalent bonds between layers meaning they can slide over each other easily
Graphite can easily conduct electricity and thermal energy because…
it contains delocalised electrons that can easily be carried along the layers
As well as graphite and diamond, Carbon also exists as…
fullerenes
Fullerenes can form…
large cage-like structures and tubes based off the hexagonal rings of carbon atoms
Fullerenes can be used for…
Transporting drugs within the body, as catalysts or as reinforcements for composite materials
What is graphene and what can it be used for?
It is a single layer of graphite, it can be used to help create new developments for electronics in the future
Atoms in metals are…
arranged closely together and in regular layers
How can you think of metallic bonding?
As positively charged metal ions that are held together by electrons from the outer shells of each metal ions.
Metals are good conductors as due to metallic bonding they have…
delocalised electrons that can easily move throughout the giant metallic lattice
Why can metals be bent and shaped?
Because layers of atoms in a giant metallic lattice can easily slide over each other
Why are alloys harder than regular metals?
The layers of metal is distorted by larger atoms of the alloy therefore meaning they cannot slide over each other
What is nanoscience?
The study of small particles between 1 and 100 nanometres in size
Nanoparticles have a high…
surface area to volume ratio
Why are nanoparticles so beneficial?
They may lead to smaller amounts of substances such as catalysts being needed in industrial processes
Why can the increased use of nanoparticles be worrying?
Possible issues may arise in terms of health problems and the environment
Nanoparticles are commonly found in…
cosmetics such as beauty products, sun creams and deodorants
