Thus carbon is but one of two or more elements in the substance sugar, and methane gas has at least one other element beside carbon. The Atom Let's consider this on the microscopic level. Here we might imagine that each substance has these tiny pieces that are too small to see. The smallest of particles of an element, those that can't be divided any further, are called atoms. To reiterate, an atom is the smallest division of an element having the properties special to the element including its chemical properties.
All atoms have basically the same structure.
The nucleus is made up of protons and neutrons. It is also very small compared to the overall size of the atom. A rough analogy of the scale of the nucleus to the atom is the relative size of a pea in a football stadium. Since each electron is about 5000 times lighter than either a proton or a neutron, almost all of the mass of the atom is at its center. These electrons fill the space around the nucleus.