| What is an ion, how do Non-metals/Metals become ions? | 1) Ion - an atom/group of atoms with a positive or negative charge (form when atoms lose or gain electrons to obtain a full outer shell)
2) metal atoms - lose electrons (to form positively charged ions)
3) non-metal atoms - gain electrons (to form negatively charged ion) |
| Do ionic compounds have high/low melt/boiling points, why? | - they have high melt/boiling points
- due to strong electrostatic forces of attraction between oppositely charged ions
- as the ionic lattice contains so many ions, lots of energy is needed to overcome the ionic bonding ∴ they have high melt/boiling points |
| Do ionic compounds conduct electricity, why? | - Only is liquid form (melted or dissolved in water to form an aqueous solution)
- because the particles are both: charged and free to move (in liquid form) |
| How is a covalent bond formed? | When 2 (non-metal) atoms share a pair of electrons from their outer shells |
| What is the typical size of a small molecule? | 0.1 nm OR 1 × 10^-10 m |
| Do small molecules have low/high melt/boiling points, Why? | - Most have low melt/boiling points
- The intermolecular forces are much weaker than the covalent bonds
- ∴ relatively small amounts of energy is needed to break these intermolecular bonds
- The bigger the molecule, the stronger the intermolecular forces, the higher the melt/boiling points |
| Do small molecules conduct electricity? | - No
- substances must contain charged particles (& be free to move from place to place)
- but small molecules have no overall electric charge (the forces cancel each other out) |
| Do giant covalent bonds have high/low melt/boiling points, Why? | - High
- large amounts of energy are needed to overcome their strong covalent bonds to make them melt or boil |
| Do giant covalent bonds conduct electricity, Why? | - Most do not (graphite does)
- most substances with giant covalent structures have no charged particles that are free to move |
| State the Structure/Bonding & Properties of Diamond. | STRUCTURE/BONDING:
- each carbon joined to 4 others by strong covalent bonds
- the carbon atoms form a regular tetrahedral network structure
- no free electrons
PROPERTIES:
- hard, due to the network of carbons held together by strong covalent bonds
- this makes it useful for cutting tools like oil rig drills
- high melting point, doesn't conduct electricity |
| State the Structure/Bonding & Properties of Graphite. | STRUCTURE/BONDING:
- each carbon joined to 3 others
- the carbon atoms form layers of hexagonal rings
- no covalent bonds between the layers
- there's 1 delocalised electron from each atom
PROPERTIES:
- conducts electricity (has delocalised electrons)
- slippery, due to weak forces between layers - they can slide over each other |
| State the Structure/Bonding & Properties of Graphene. | STRUCTURE/BONDING:
- 1 atom thick, It's a single layer of graphite (refer to the previous flash card)
PROPERTIES:
- high melting point (due to strong covalent bonds)
- very strong
- conducts electricity, due to the delocalised electrons that are free to move |
| What is a Fullerene, what is Buckminster fullerene? | - Molecules of carbon with hollow shapes, their structures are based of hexagonal rings (however sometimes they have 5 or 7 rings) of carbon
- Buckminster fullerene - sphere containing 60 carbons, arranged in hexagonal rings (6 carbons on each ring) |
| What are some uses of Fullerenes? | - Deliver pharmaceutical drugs
- lubricants (stop grinding)
- catalysts (speed up chemical reactions)
- (nanotubes:) tennis rackets - for reinforcement |
| What are carbon nanotubes, give Properties? | - Carbon nanotubes are cylinders of fullerenes
PROPERTIES:
- high tensile strength (stretched without breaking)
- good heat & electricity conductors
- high surface area : volume ratio |
| What are Polymers & what are their properties? | - Polymers have very large molecules joined together by strong covalent bonds
PROPERTIES:
- Strong intermolecular forces
- therefore, high melt/boiling points |
| State the Structure/Bonding & Properties of Metals. | STRUCTURE/BONDING
- outer shell electrons are delocalised, ∴ free to move through the whole structure
PROPERTIES:
- conduct electricity - their delocalised electrons carry electrical charge through the metal
- good conductors of thermal energy - their delocalised electrons transfer energy
- have high melt/boiling points - the metallic bonding in the giant structure of a metal is very strong - large amounts of energy are needed to overcome the metallic bonds in melting and boiling
- Can be bent/shaped - the layers can slide over each other |
| Why are Alloys sometimes more useful than pure metals? | - they are harder, it's more difficult to bend them
- this is because alloys are made up of different metals with atoms of different sizes
- this distorts the layers ∴ it's harder for them to slide over each other |
