Ionic, Covalent and Metallic Bonding (2)

Question 1

Describe what happens when two atoms of potassium react with one atom of sulfur

Answer 1

Electrons are transferred from potassium to sulfur where two potassium atoms each lose one electron forming 1+ ions and sulfur atoms gain 2 electrons forming 2- ions

Question 2

The ball and stick model is not a true representation of the structure of potassium sulfide.
Give one reason why

Answer 2

There are no gaps between the potassium and sulfide ions

Question 3

Low melting point goes to ….
Does not conduct electricity when molten goes to ….

Answer 3

• weak intermolecular forces of attraction
• there are no charged particles free to move

Question 4

State two observations that could be made during the reaction

Answer 4

• fizzing
• bubbles of gas

Question 5

Explain how electricity is conducted in a metal

Answer 5

Giant structure made up of atoms with delocalised electrons which can move through the metal

Question 6

Describe how the structure of an alloy is different from the structure of a pure metal

Answer 6

An alloy is a metal which has different sizes of atoms. Alloy has distorted layers.

Question 7

Why is Ninotol used in dental braces?

Answer 7

Can return to its original shape

Question 8

Suggest one reasons why coins are not made of pure copper

Answer 8

Pure copper is too soft

Question 9

Aluminium is manufactured by the electrolysis of a molten mixture of cryolite and

Answer 9

Aluminium oxide

Question 10

How can the same reaction produce two different products?

Answer 10

Different conditions

Question 11

Suggest one error that the student may have made to cause the anomalous result

Answer 11

Didn’t stir the solution properly

Question 12

State one variable he should keep constant when measuring the conductivity of the two solutions

Answer 12

Volume of pure water

Question 13

Explain why chlorine is gas at room temperature, but sodium chloride is a solid at room temperature

Answer 13

Chlorine contains covalent bonds between atoms forming simple molecules. There is almost no attraction between the molecules in chlorine so it has a low boiling point. Sodium chloride contains ionic bonds which are strong and act in all directions between oppositely charged ions forming giant lattice. Therefore, sodium chloride has a high melting point as a large amount of energy is needed to break the bonds