C2 Flashcards
What are the 3 bonds?
Ionic, covalent and metallic
Summary for ionic bonding?
1 positive metal ion and 1 negative non-metal ion. Transfers electrons from metal to non-metal and then the ions are strongly attracted to each other with electrostatic forces.
Summary for covalent bonding?
2 non-metal atoms which share electrons. Attracted together by strong electrostatic forces.
Summary for metallic bonding?
2 metal atoms which share delocalised electrons. Electrostatic attraction between positive nuclei and negative shared electrons.
What’s the diagram for ionic bonding?
Dot and cross diagram
What is an ionic compound?
A giant structure of ions held together by strong electrostatic forces of attraction between oppositely charged ions.
What are the limitations of the dot and cross diagram?
They don’t show:
- Structure of compound
- Size of ions
- How they’re arranged
What are the limitations of ball and stick diagram?
It’s not to scale. There are in fact no gaps between ions.
What’s the empirical formula?
Just basically the regular formula
e.g. K2O
What type of structure does most gases have?
Simple covalent structure.
What type of structure does sodium chloride and magnesium chloride have?
Giant ionic structure.
What type of structure does diamond, graphite, graphene and fullerenes have?
Giant covalent structure.
What type of structure does gold, copper and zinc have?
Giant metallic structure.
What type of structure does steel and bronze have?
Giant metallic structure.
Why can’t most gases conduct electricity?
No ions, no delocalised electrons (which usually carry charge).
How can sodium chloride and magnesium chloride conduct electricity?
When liquid, the ions can move and carry charge through the structure.
Why can’t sodium chloride and magnesium chloride conduct electricity?
When solid, the ions can’t move.
Why can’t diamond conduct electricity?
Each carbon makes 4 strong bonds so there are no spare electrons so no delocalised electrons (which usually carry charge).
Why can graphite, graphene and fullerenes conduct electricity?
Each carbon makes 3 strong bonds so there’s a spare electron. So, there’s delocalised electrons which carry charge and move through the structure.
Why can metals conduct electricity?
They have delocalised electrons which move and carry charge through the structure.
What are limitations of the solid, liquid, gas diagram?
There are no forces included, all particles are spheres and the spheres are solid.
Which state has the highest boiling and melting point?
Solid
Which state has the most energy?
Gas
What’s an ionic compound?
Structure with strong electrostatic forces of attraction between oppositely charged ions.
Why do ionic compounds have high melting and boiling points?
Large amount of energy needed to overcome the strong bonds.
Summary about polymers
- Very large molecules
- Atoms linked to other atoms by strong covalent bonds.
- Relatively strong intermolecular forces between molecules.
Why are alloys harder than pure metals?
Because they have differently sized particles with uneven layers so they cannot easily slide over each other like pure metals can.
In graphite what forces are in between layers?
Weak forces
What is graphene useful for?
Electronics and composite materials
What is a fullerene?
Fullerenes are molecules of carbon atoms with hollow shapes.
What was the first fullerene discovered?
Buckminsterfullerene (C60) (sphere)
What do carbon nanotubes have?
They are cylindrical fullerenes with very high length to diameter ratios.
How are carbon nanotubes useful?
Nanotechnology, electronics and materials.
What does nanoscience refer to?
Structures 1-100nm.
What’s the order for tiny particles?
Nanoparticles 1-100nm
Fine particles 100-2500nm
Coarse particles (dust) 2500-10000nm
What do nanoparticles have as a property?
High surface area to volume ratio.
What happens as a side of a cube decreases by a factor of 10?
The surface area to volume ratio increases by a factor of 10.
What are some uses of nanoparticles?
Medicine, electronics, cosmetics, sun cream, deodorant, catalysts.
What are some advantages of nanoparticles?
Small so less can be used for same effect. Environmentally friendly.
What are some disadvantages of nanoparticles?
If absorbed into skin, could be toxic.
