Identify each of the following materials as being an element, a mixture or a compound;?

Aluminium foil; North Sea Oil; a piece of granite rock; a cup of coffee; C9H13N; milk; the helium in a balloon.

The atom has 13 electron because every atom has the same number of protons as electronsLook up what an Ion is on wikipedia.

Aluminium foil - element North Sea Oil - mixture a piece of granite rock - compound a cup of coffee - mixture C9H13N - compound milk - mixture the helium in a balloon - element So simpleGoodluck to you!