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level: Bonding, Structure and Properties of Matter

Questions and Answers List

level questions: Bonding, Structure and Properties of Matter

QuestionAnswer
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.