X-Ray used to Take images of teeth and bones.
Ultraviolet night vision goggle
Water containing carbonic acid and calcium
If it is located at the second to last row of the periodic table (the halogen family), has seven electrons on it's outer shell, and has an oxidation number of -1, it is a halogen.
Hope this helps : D
I disagree, because a physical change changes the form, and a chemical change is a process where one or more substances are altered into new substances.