C3 - Structure and Bonding Flashcards
What are the 3 states of matter?
- Solid, liquid and gas.
What are the particles like in a solid?
- Packed closely together.
- Vibrate around fixed positions.
What are the particles like in a liquid?
- Also close together.
- Can slip and slide over each other in random motion.
What are the particles like in a gas?
- Lots of space between them and zoom around randomly.
What happens in melting and boiling in the states of matter?
- Energy is transferred from the surroundings to the substance.
What happens in freezing and condensing in the states of matter?
- Energy is transferred from the substance to the surroundings.
How do elements form to create compounds?
- By gaining or losing electrons or by sharing electrons.
What happens in a reaction between group 1 elements and group 7 elements (halogens)?
- Atoms of group 1 elements can lose one electron to gain the stable electronic structure of a noble gas.
- The electron can be given to an atom from group.7 which will also now have the electronic structure of a noble gas.
What ions do group 1 form?
- 1+ ions.
What ions do group 2 form?
- 2+ ions.
What ions do group 3 form?
- 3+ ions when they form ions as opposed to sharing electrons.
What ions do group 4 form?
- They do not form ions; however, led and tin form ions at the bottom of the group.
What ions do group 5 form?
- 3- ions when they form ions as opposed to sharing electrons.
What ions do group 6 form?
- 2- ions when they form ions as opposed to sharing electrons.
What ions do group 7 form?
- 1- ions when they form ions as opposed to sharing electrons.
What ions do group 0 form?
- Never form ions in compounds.
How are ionic compounds held together?
- Strong forces of attraction between their oppositely charged ions
- This is called ionic bonding.
What ions can form ionic compounds?
- Group 1 and group 7.
- Group 2 and group 6.
Features of strong ionic bonds.
- Operate in all different directions holding a giant ionic lattice together, therefore ionic compounds have high melting points; they are all solid at room temperature.
Features of ionic compounds.
- Conduct electricity when molten or dissolved in water.; their ions can then become mobil and carry charge through the liquid.
What is a covalent bond?
- When non-metals are bonded together.
How are covalent bonds formed?
- When atoms of non metals share pairs of electrons together.
- Each shared pair of electrons is a covalent bond.
What do many substances with covalent bonds have?
- Consist of simple molecules but have some giant covalent structures.
What are the boiling points of simple molecule substances likely to have?
- Low melting and boiling points.
What are the forces of simple molecules like?
- They are weak; the weak intermolecular forces explain why substances made of simple molecules have low melting and boiling points.
What is the charge like in simple molecules?
- No overall charge, therefore they cannot carry electrical charge.
- Substances of simple molecules cannot conduct electricity.
Why are models used to show bonding?
- To help the understanding of its bonding but each models has its limitations in representing reality.
What are giant covalent structure substances’ boiling points like?
- Very high - melting and boiling points.
What are the giant covalent bonds like in graphite?
- Giant layers of covalently bonded carbon atoms.
- No covalent bonds between the layers.
- They can slide over each other, making graphite soft and slippery.
- Carbon atoms in diamond have a rigid giant covalent structure making it a very hard structure.
Can graphite conduct electricity?
- Yes.
- Also can conduct thermal energy because of the delocalised electrons that can move along its layers.
What are fullerenes?
- As well as diamond and graphite, carbons also exists in fullerenes, which can form large cage-like structures and tubes, based on hexagonal rings of carbon atoms.
What are fullerenes being used for?
- Finding uses as a transport mechanism for drugs to specific sites in the body, as catalysts, and as a reinforcement for composite materials.
What is graphene and what properties does it possess?
- A single layer of graphite and so is just one atom thick.
- Its properties: excellent electrical conductivity; will help create new developments in the electronics industry in the future.
What are the atoms like in metals?
- Closely packed together and arranged in regular layers.
How can you think of metallic bonding?
- Positively charged metal ions held together by electrons from the outermost shell of each metal atom.
- These delocalised electrons are free to move throughout the giant metal lattice.
What are metals like in a giant metallic structure?
- Can be bent or shaped because the layer of atoms (or positively charged ions) can slide over each other.
Why are alloys harder than pure metals?
- Regular layers in a pure metal are distorted by atoms of different sizes in an alloy.
What delocalised electrons in metals do?
- Enable electricity and thermal energy to be transferred through metal easily.
