The table generated by arranging elements according to their atomic numbers and energy shells 15. Find the symbol and the atomic mass of each of the following elements by using the periodic table. Distinguish between an atom and a molecule. An atom is the smallest unit of an element that has the element's chemical properties. A molecule is the smallest unit of any substance that has all the substance s chemical properties.
Atoms combine to form molecules.
There are only 115 distinct atoms, which combine to form a great variety of molecules. Give a few examples for each. A compound is made of two or more different elements which are chemically combined. A mixture is made of substances mixed together without chemically combining. Examples are air, wine, and salt mixed with sand.