Matter has mass and takes up space. Atoms are basic building blocks of matter, and cannot be chemically subdivided by ordinary means. The word atom is derived from the Greek word "Atom" which means indivisible. The Greeks concluded that matter could be broken down into particles too small to be seen. These particles were called atoms. All atoms are too small to be seen with the naked eye or even a microscope, although there are some new types of microscopes that enable us to see larger atoms such as gold. Atoms are made up of even smaller particles called electrons, protons, and neutrons. Electrons and protons have electric charges, but neutrons do not. Atoms are not separate, but are linked to other atoms. These linked atoms are called as molecules.