Topic 2 - Bonding, structure and Properties of Matter Flashcards
Describe ionic bonding and ionic compounds properties
Ionic bonding is between a metal and non-metal. Electrons are transferred from the metal to the non-metal so the metal loses electrons and becomes positively charged. The non-metal gains electrons and becomes negatively charged. The metal loses electrons and becomes positively charged.
Ionic compounds have a giant ionic structure and strong electrostatic forces of attraction with high melting and boiling points as they require a lot of energy to break the strong bonds. Ionic compounds can conduct electricity when it has been melted to a liquid because the electrons are free to move and carry electrical charge.
What is covalent bonding?
Covalent bonding:
— Bonding between a non-metal and non-metal and share a pair of electrons to gain a full outer shell.
What are some limitations of using dot and cross, ball and stick or any 2d or 3d diagram to represent bonding?
- – Dot and cross diagrams do not show the actual size or how the atoms are arranged.
- – Ball and stick for ionic compounds only show the outer layer of the compound and is not to scale.
Explain metallic bonding in as much detail as possible.
Metallic bonding is the bonding between two metals with a strong electrostatic force of attraction which means they have high melting and boiling points as they require a lot of energy to break the bonds. The outer shell electrons are delocalised therefore metals are good conductors of heat and electricity.
What are properties of small molecules?
- – Tend to be liquids or gases with low melting and boiling points
- – Strong covalent bonds but weak intermolecular forces so not a lot of energy is required to break the intermolecular forces.
- – As size of molecules increase, intermolecular forces increase so higher melting and boiling points
- – Cannot conduct electricity as there is no overall charge
What is a polymer? What are properties of polymers?
Polymer:
— A polymer is a long chain of repeated small units
Properties:
- – Contain large molecules
- – Strong intermolecular forces but still weaker than ionic or giant molecular structures
- – Solid at room temperature
- – Strong covalent bonds
What are properties of giant covalent structures? Give three examples.
- – Strong covalent bonds
- – High melting and boiling points
- – Strong intermolecular forces
- – Solids at room temperature
Examples are graphite, diamond and silicon dioxide
What are the differences between alloys and pure metals?
Pure metals are often too soft for many uses as they are arranged in layers all made up of the same type of metal. However, alloys are made up of different sizes of atoms and is not arranged in layers so they cannot slide over each other which makes them harder than pure metals
What is the structure and bonding of diamond and graphite?
Diamond is very hard as it covalently bonded to four other carbon atoms therefore it cannot conduct electricity as there are no delocalised electrons. It also has very strong covalent bonds which require a lot of energy to break the bonds so diamond has a high melting and boiling points.
Graphite is quite soft as it is covalently bonded to three other carbon atoms so there are delocalised electrons therefore it can conduct electricity. Graphite forms layers of hexagonal rings without covalent bonds between each layer so the layers can slide over each other. Graphite has a high melting point.
What is graphene and how is it useful in composites or electronics?
Graphene is one layer of graphite. It is useful in composites as it has lot of strong covalent bonds which make composites stronger. It is useful in electronics as the delocalised electrons allow electronics to conduct electricity
What are fullerenes and what are some examples of uses?
Fullerenes are molecules of carbon that form hollow shapes. Three uses of fullerenes are nanotubes, deliver drugs around body, lubricants or catalysts.
