Substance composed of molecules each of which contains two iodine atoms

A substance that is made up of molecules, each of which contains two iodine atoms is called an element.

A species of atoms having the atomic number and the same number of protons in their atomic nuclei (i. e. the same atomic number, or Z). is called a chemical element or simply element. 118 elements were already identified, and the first 94 of them occur on Earth naturally, while the remaining 24 are synthetic elements. Even with chemical means, elements cannot be broken down into simpler substance. The most common element in the Earth’s crust that is known to mankind is oxygen.