What are elements and compounds? Give examples of each.

Here are the answers for Question 3:

3.1 Hydrogen
Hydrogen is an element.
It cannot be broken down into different elements.

3.2 Water
Water is a compound.
It can be broken down into different elements: Hydrogen and Oxygen.

3.3 Iron
Iron is an element.
It cannot be broken down into different elements.

3.4 Sulfur dioxide
Sulfur dioxide is a compound.
It can be broken down into different elements: Sulfur and Oxygen.