Atom

  

                                        ATOM

An atom is the smallest unit of an element that keeps its chemical identity. Imagine taking a piece of pure gold and cutting it into smaller and smaller pieces; the smallest piece you could possibly have while still being "gold" is a single atom.

At the center of every atom lies a tiny, dense nucleus containing positive protons and neutral neutrons. Zipping around this nucleus are much smaller, negative electrons, which move in specific paths called shells or orbits. Even though atoms make up everything we see, they are mostly empty space—if an atom were the size of a sports stadium, the nucleus would be like a small marble in the middle, and the electrons would be like tiny grains of sand in the very back rows!