Which one of the following groups consists of one mixture,

one element and one compound?

1. Aluminium, water and nitrogen gas

2. Aluminium, steel and air

3. Air, water and iron oxide

4. Calcium, soil and sodium chloride

The answer is 4. Because of the metals.

4.

Explanation:

1. Aluminium - element, water - compound and nitrogen gas - element

2. Aluminium - element, steel - mixture and air - mixture

3. Air - mixture, water - compound and iron oxide - compound

4. Calcium, - element soil - mixture and sodium chloride - compound