Choose the word which is different from the rest.

The answer is C. Iodine.

Hydrogen, oxygen, nitrogen, and chlorine are all elements in the same group of the periodic table, the halogens. Halogens are highly reactive elements that form salts with metals. Iodine is the only non-metal in this group.

Hydrogen is the lightest element in the universe. It is a colorless, odorless, and tasteless gas that is essential for life. Oxygen is a colorless, odorless, and tasteless gas that is essential for respiration. Nitrogen is a