Topic 2 - Bonding, Structure And Properties Of Matter Flashcards
When are ions made?
When electrons are transferred
Why do atoms lose/gain electrons to form ions?
To get a full outer shell
When metals form ions, do they lose or gain electrons?
Lose electrons to form positive ions
When non-metals form ions, do they lose or gain electrons?
Gain electrons to form negative ions
Which groups are most readily to form ions?
Groups 1,2 and 6,7
What is ionic bonding?
Sharing electrons.
Metal + non metal
What is the structure of ionic compounds?
They have a structure called a giant ionic lattice.
The ions form a tightly packet regular lattice arrangement there are very strong forces of attraction between oppositely charged ions.
What are properties of ionic compounds?
High melting and boiling points due to strong bond between ions.
Cant conduct energy when solid but they can when liquid as the ions are free to move.
Dissolve easily in water.
What is covalent bonding?
When 2 non-metals bond.
They share electrons to make covalent bonds.
What are properties of simple molecular substances? (Eg H2 CL2 H2O)
Forces of attraction between molecules are weak but atoms within them have strong covalent bonds.
Low melting and boiling points to break intermolecular forces.
Gases or liquids at room temp.
As molecules get bigger, intermolecular forces are stronger so higher boiling and melting points.
Dont conduct electricity as they arent charged.
What is a simple molecular substance?
They are made up of molecules containing atoms joined together by covalent bonds. Eg O2
What is a polymer?
Long chains of repeating units.
There are lots of small units linked together to form a long molecule.
How are atoms bonded in a polymer?
Covalently
Do polymers have high or low boiling points?
Low
What are features and examples of giant covalent structures?
In giant covalent structures, all atoms are bonded to each other by strong covalent bonds.
High melting/boiling points as lots of energy required to break bonds between atoms.
Dont conduct electricity.
Eg diamond, graphite, silicone
What is an allotrope
Different structural forms of the same element
What are the 4 allotropes of carbon?
Diamond
Graphite
Graphene
Fullerene
What are features of diamond?
Made of carbon atoms that each form 4 covalent bonds. This forms a giant covalent structure
These strong bonds give diamond high melting point.
Doesnt conduct electricity since no free electrons or ions
What are features of graphite?
Each carbon atom forms 3 covalent bonds. This forms sheets of carbon atoms arranged in hexagons.
No covalent bonds between sheets makes graphie soft and slippery so ideal lubricant.
High melting point.
Can conduct electricity and heat as each carbon atom has 1 delocalised electron.
What are features of graphene?
Just one sheet of carbon atoms joined in hexagons. 1 atom thick.
Covalent bonds makes it very strong yet its very light.
Can conduct electricity since each carbon atom has 1 delocalised electrons.
What are fullerenes?
They are molecules of carbon shaped like hollow balls.
Buckminster fullerene was the first fullerene to be discovered.
What are uses of fullerenes?
Can be used to cage other molecules. Can use this function to deliver a drug into the body.
Have huge surface area so can help make great industrial catalysts(individual catalyst molecules can be attached to fullerenes).
Also make good lubricants.
How can fullerenes be used in nanotechnology?
Fullerenes can form nanotubes.
Ratio between length and diameter of nanotubes is very high.
Nanotubes can conduct electricity and heat.
High tensile strength.
Can be used in electronics or to strengthen materials without adding much weight.
How does metallic bonding work?
Involves delocalised electrons in outer shell of metals and their are strong forces of attraction between these shared negative electrons and position metal ions.
