C2: Structure and Bonding Flashcards
Describe ionic bonding.
Metals transfer their electrons to non-metals, creating a positive metal ion and negative non-metal ion. (LIP/GIN) Strong electrostatic attraction holds the two oppositely charged ions together.
Describe covalent bonding.
Two non-metals share pairs of electrons to form strong covalent bonds.
Describe metallic bonding.
Two metals bond through sharing a sea of delocalised electrons, creating strong electrostatic attraction between the electrons and the ions.
How do you work out the charge of an element’s ion?
By looking at the group number, which shows the number of outer shell electrons, and determining how many electrons should be lost/gained to make a full outer shell. Loss is Positive, Gain is Negative.
What does LIP/GIN stand for?
Loss is positive, gain is negative. (of electrons)
What should you always remember when drawing an ionic bonding diagram?
- Representing electrons, one ion has dots, the other has crosses.
- Both have brackets and charges around the outside.
Describe 2 limitations of using dot and cross diagrams to represent ionic structure.
- They don’t show the 3D arrangements of the atoms and electron shells.
- They don’t show the relative sizes of the atoms.
What is an ionic compound?
A giant structure of ions, held together by strong electrostatic forces between oppositely charged ions. These forces act in all directions in the lattice.
Why can ionic substances only conduct electricity when molten or dissolved?
Because when molten or dissolved, the ions and electrons are free to move and carry charge.
Why do ionic compounds have high melting and boiling points?
They have a high boiling point because much energy is needed to overcome the strong electrostatic attraction.
Describe the properties of ionic compounds.
They only conduct electricity when molten or dissolved and they have high melting and boiling points.
Describe the properties of giant covalent structures.
They have high melting and boiling points and cannot conduct electricity.
Why do giant covalent structures have high melting and boiling points?
They have a high boiling point because much energy is needed to overcome the strong covalent bonds.
Why can’t giant covalent structures conduct electricity?
Because they have no electrons that are free to move and carry charge.
Why are metals good at conducting electricity?
Because they are metallically bonded, so contain a sea of delocalised electrons that are free to move and carry charge.
What are the limitations of the particle model of the states of matter?
They don’t show forces, and all particles are represented as solid spheres, which isn’t accurate.
What should you remember when writing ionic equations?
State symbols.
What are the 4 state symbols?
(s) - solid
(l) - liquid
(aq) - aqueous
(g) - gas
What is an aqueous solution?
A type of solution in which water is the solvent.
What is a simple molecule?
Usually a gas or liquid, bonded by weak intermolecular forces.
What are the properties of simple molecules?
Relatively low melting and boiling points. (M/B point increases as simple molecules get bigger). They don’t conduct electricity.
Why do simple molecules have low melting and boiling points?
Because less energy is needed to overcome the weak intermolecular forces.
Why don’t simple molecules conduct electricity?
Because the molecules do not have an electric charge.
What is a polymer?
Very large molecules linked by covalent bonds, with strong intermolecular forces between molecules, so they are solid at room temperature.
Why might a substance be a solid at room temperature?
Because it has a high melting and boiling point.
Why might a substance be a gas at room temperature?
Because it has a low melting and boiling point.
Describe the structure and properties of Diamond.
- Carbon allotrope.
- Each carbon atom forms 4 covalent bonds with other carbon atoms.
- It has a giant covalent structure.
- So diamond is very hard, has a very high melting point and does not conduct electricity.
Describe the structure and properties of Graphite.
-Carbon allotrope.
- Each carbon atom forms 3 covalent bonds with three other carbon atoms.
- It has layers of hexagonal rings which have no covalent bonds between the layers.
- 1 electron from each carbon atom is delocalised.
-So graphite is
Describe the structure and properties of Graphene.
What is an allotrope?
Name the 3 main allotropes of carbon.
Diamond, Graphite and Graphene.
Describe the properties of metals.
High melting and boiling points, and good conductors of electricity.
Why do metals have high melting and boiling points?
Because they have many strong electrostatic forces which take much energy to overcome.
Why are metals good conductors of thermal energy?
Because energy is transferred by the delocalised electrons.
What is an alloy?
A mixture of 2+ elements, where at least 1 is a metal.
What are nanoparticles?
What are the 6 uses of nanoparticles?
- Medicine.
- Cosmetics.
- Sun creams.
- Deodorants.
- Catalysts.
- Electronics.
What are the risks of using nanoparticles?
Name 3 nanoparticle structures.
Buckminsterfullrene, Graphene, Nanotubes.
