| What are ions? | Atoms or groups of atoms that have a charge because they lose or gain electron(s). |
| What forms negatively charged ions? | Non-metals form negatively charged ions. |
| What are negatively charged ions called? | Anions. |
| What forms positively charged ions? | Metals form positively charged ions. |
| What are positively charged ions called? | Cations. |
| What are dot and cross diagrams? | Diagrams that show how ionic bonds are formed by showing the arrangement of electrons in an ion or atom. |
| Draw and explain the dot and cross diagram of Sodium Chloride. | The sodium atom gives the outer electron to have a full outer shell. It then becomes Na⁺. The chlorine atom then gains the electron to also have a full outer shell, and becomes Cl⁻. |
| What is an advantage of dot and cross diagrams? | It shows where electrons have moved from.
It shows the electron arrangement. |
| What are some disadvantages of dot and cross diagrams? | It doesn't show how the ions are arranged.
It doesn't show the size of the substance. |
| Draw a dot and cross diagram of Magnesium Chloride. | The magnesium atom gives two electrons to then have a full outer shell. It becomes Mg²⁺. The two chlorine atoms gain an electron each, so now they also have full outer shells. We now have two Cl⁻ ions. |
| What are ionic compounds called? | Giant ionic lattices. |
| What is a ball and stick model? | A model that shows the atoms and the bonds between them in a 3D representation of covalent structures. |
| What are some advantages of 2D models? | It is simple.
It shows the atoms involved.
It shows how the atoms are connected. |
| What are some disadvantages of 2D models? | It does show the shape.
It doesn't show the size. |
| What are some advantages of ball and stick models? | It shows how atoms are arranged.
It also shows the covalent bonds between ions.
It shows the shape. |
| What are some disadvantages of ball and stick models? | There aren't actually gaps between the ions.
It also doesn't show it to relative size. |
| What are some advantages of 3D ionic structures? | It shows how big the ions are compared to each other.
It shows how they are ordered in a pattern. |
| What are some disadvantaged of 3D ionic structures? | It doesn't show the bonds between ions.
It only shows the outside layers. |
| Why can ions not conduct when molten? | Because the ions are not free to move. |
| Why can ions conduct when molten or aqueous? | Because the ions are now free to move, they can carry charge throughout the structure. |
| What is an ionic bond? | The electrostatic force of attraction between oppositely charged ions. |
| What is empirical formula? | The ration of the different atoms in a compound in its simplest form. |
| What is the empirical formula of the ionic compound potassium oxide? | Potassium is in group 1, so it makes a 1+ ion.
Oxygen is in group 6, so it makes a 2- ion.
To make the charge neutral, we need 2 potassium ion for every 1 oxygen ion.
= K₂O. |
| What are covalent bonds? | The sharing of electrons between non metals. They are very strong and have intermolecular forces keeping them together. |
| What are intermolecular forces? | Forces of attraction between molecules. They are weak. |
| What are the three different ways to draw covalent bonds? | Dot and cross diagrams, Displayed formula and 3D models. |
| What are some simple molecular substances? | Hydrogen, Chlorine, Oxygen, Nitrogen, Methane, Water and Hydrogen Chloride |
| What are simple molecular substances made up of? | Molecules containing few atoms joined by covalent bonds. |
| What are some properties of simple molecular substances? | They have low melting and boiling points.
They have simple molecular structures.
They are gases or liquids at room temperature.
They don't conduct. |
| What is an advantages of (displayed) formulas? | They show how atoms are connected in large molecules. |
| What are displayed formulas and what are some disadvantages? | Something that shows the atoms and bonds of a compound, with the bonds shown as lines.
They don't show the 3D structure.
They don't show which atom the electron came from. |
| What is a 3D models and what are some advantages? | A ball-and-stick model that shows 3 dimensional shape/ configuration of a molecule.
They show the atoms.
They show the covalent bonds.
They show how it's arranged. |
| What is a molecule? | A group of atoms that are covalently bonded together. |
| What is a giant covalent structure? | A structure that is made up of many atoms that are strongly covalently bonded together. They have high melting and boiling points. |
| What are the two main forms of carbon? | Diamond and graphite. |
| What is diamond? | A giant covalent structure that has a high melting and boiling point. It is very hard and each carbon has 4 covalent bonds. this means there are no delocalised electrons, so it's a bad conductor. |
| What is graphite? | A giant covalent structure that has a high melting and boiling point. Each carbon atom has 3 covalent bond, so it has delocalised electrons. This means it is a conductor. |
| Explain why graphite is soft and slippery. (4 marks)
OR
Graphite is used in lubricants, explain why it's used this way. (4 marks) | Because each carbon atom forms 3 strong covalent bonds, the delocalised electrons between the layers create weak intermolecular forces of attraction, meaning they can easily slide over each other. This means they don't have a lot of friction. |
| Explain why diamond is hard. (4 marks)
OR
Diamond is used in drills and cutting blades, explain why it's used this way. (4 marks) | Diamonds are hard because it has 4 very strong covalent bonds between each carbon atom. This means it has a high melting and boiling point. So, it needs lots of energy to overcome these bonds because it's also a giant covalent structure. |
| What is a polymer? | A long chain or repeating molecules called monomers. |
| What is graphene? | A single layer of graphite which can conduct electricity better than copper. |
| What is fullerene? | Hollow tubes of carbon molecules. |
| What are carbon nanotubes? | Graphene folded into sheets. |
| What is buckminsterfullerene? | C₆₀ in hexagons and pentagons. |
| How would you draw polymers? | By drawing repeating units, you avoid drawing the long polymer molecule. |
| Carbon nanotubes are cylindrical fullerenes. Explain its properties. Answer in terms of structure and bonding. | It has a high melting point because of its strong covalent bonds. It also has a high electrical and thermal conductivity because of their delocalised electrons carry charge through the structure. |
| What is the structure of giant ionic lattices made up of? | Oppositely charged ions. |
| Can covalently bonded structures conduct? | No, expect graphite. |
| What makes metallically bonded structures pure? | It's made pure when it consists of the same element in a regular arrangement of positive atoms. |
| What makes metallically bonded structures an alloy? | It's an alloy when it consists of different elements in layers that are distorted and can't slide over each other easily. |
| Why do simple molecular substances have low melting and boiling points? | Because it's a simple molecular substance, it has weak intermolecular forces of attraction. This means that not a lot of energy is needed to overcome them, so they have low melting and boiling points. |
