Elements join together to make molecules and form familiar substances such as water, sugar, and salt.

When elements are mixed, their properties do not change. For instance, sulfur (S) looks like a yellow powder. The powder comes from a solid that has been ground up into little pieces. Iron (Fe) can be ground up into little gray-black pieces which we call iron filings. Iron is one of the metals that is attracted to a magnet.

Now imagine that you mix the sulfur with the iron. You would still be able to see the yellow sulfur powder and the gray-black iron filings. This is a mixture. If you wanted to separate the two, you could hold a magnet over the pile and the iron would stick to the magnet and leave the sulfur behind. The individual properties of the elements sulfur and iron did not change when they were mixed together.

You also have a mixture if you take salt and dissolve it in water. You can’t see the salt, but by a simple physical process (evaporating the water), you can get the salt and water back, and they haven’t lost any of their chemical properties. You end up with the same molecules you started with.