1. Describe how potassium atoms are formed from potassium ions.
A.
Each potassium ion gains two electrons.
B.
Each potassium ion loses an electron.
C.
Each potassium ion (K+) gains one electron.
D.
Each potassium ion loses two electrons.
2.
2. Why is methane a gas at room temperature?
A.
There are only weak intermolecular forces that hold the molecules together so only small amounts of energy are needed to overcome these forces.
B.
There are only weak covalent bonds that hold the molecules together so only small amounts of energy are needed to overcome these forces.
C.
There are only weak ionic bonds that hold the molecules together so only small amounts of energy are needed to overcome these forces.
D.
There are weak intermolecular forces that hold the atoms together so only small amounts of energy are needed to overcome these forces.
3.
3. What is a covalent bond?
A.
A transfer of electrons.
B.
A shared pair of electrons.
C.
Bonds between molecules that require lots of energy to overcome.
D.
When one atom donates a pair of electrons to another atom.
4.
4. What is an ionic bond?
A.
A shared pair of electrons
B.
The electrostatic attraction between oppositely charged ions.
C.
Bonds between molecules that require lots of energy to overcome.
D.
When one atom donates a pair of electrons to another atom.
5.
5. Why are high temperatures needed to melt ionic substances?
A.
Ionic substances have a giant covalent structure. A lot of energy is needed to overcome the strong electrostatic attraction forces between the oppositely charged ions.
B.
Ionic substances have a simple molecular structure. A lot of energy is needed to overcome the strong electrostatic attraction forces between the oppositely charged ions.
C.
Ionic structures have giant ionic structures. A lot of energy is needed to overcome the weak intermolecular forces between the molecules.
D.
Ionic substances have giant ionic structures. A lot of energy is needed to overcome the strong electrostatic attraction forces between the oppositely charged ions.
6.
6. Why does sodium chloride in water conduct electricity?
A.
The ions are free to move to carry charge.
B.
Electrons are free to move to carry charge.
C.
Ions and electrons are free to move to carry charge.
D.
Sodium is a metal so can conduct electricity.
7.
7. Why is the melting point of NaCl high, whereas the melting point of CO2 is so low?
A.
NaCl contains a metal which means it will have a much high melting point than CO2 which only contains non metals.
B.
NaCl has a giant ionic structure, so has strong electrostatic attractions between ions; CO2 has a giant covalent structure which has strong covalent bonds between atoms, however NaCl's bonding is stronger so has a higher melting point.
C.
NaCl has a giant covalent structure, so has strong covalent bonds between atoms; CO2 has a simple molecular structure and therefore has weak intermolecular forces between molecules.
D.
NaCl has a giant ionic structure, so has strong electrostatic attractions between ions; CO2 has a simple molecular structure and therefore has weak intermolecular forces between molecules.
8.
8. Why does graphite rub off a pencil onto paper?
A.
There are only weak electrostatic attractions between the ions in graphite. These are easily broken so that the layers can slide and transfer onto the paper.
B.
The layers have metallic bonding and due to the delocalised electrons these can move. This makes the bonding between layers weaker and they can slide.
C.
There are only weak intermolecular forces between the layers in graphite. These are easily broken so that the layers can slide and transfer onto the paper.
D.
Graphite is very brittle. This means that when it comes into the contact of paper the layers break off and transfer to the paper easily.
9.
9. Why is silicon dioxide a suitable material for lining furnaces.
A.
The giant ionic lattice has a very high melting point which makes it suitable for the high heat of a furnace.
B.
The metallic structure of silicon dioxide has a very high melting point which makes it suitable for the high heat of a furnace.
C.
The giant ionic lattice has delocalised electrons which helps repel the high heat of the furnace.
D.
The giant covalent structure has a very high melting point which makes it suitable for the high heat of a furnace.
10.
10. Why do metals conduct electricity?
A.
Metals have a giant metallic structure which contains delocalised electrons. These are able to move and carry charge.
B.
Metals have a giant metallic structure which contains ions. These are able to move and carry charge.
C.
Metals have a giant metallic structure which contains delocalised protons. These are able to move and carry charge.
D.
Metals have a simple metallic structure. The bonding between the metal ions is weak meaning they are able to move and carry charge.
11.
11. Which image represents the structure of graphite?
