Atom explained to kids

An atom is the smallest particle of an element that has the chemical properties of that element. Atoms are made up of protons and neutrons in the nucleus (center) of the atom with electrons orbiting around this nucleus. The word "atom" comes from the Greek word for indivisible, because it was once thought that atoms were the smallest things in the universe and could not be divided. We now know that atoms can be divided, but only with special equipment. Atoms of different elements have different numbers of protons in their nucleus. The number of protons in an atom's nucleus is called the atom's atomic number. For example, all atoms of carbon have 6 protons in their nucleus. Atoms of different elements have different chemical properties. This means that atoms of different elements will react differently when they are combined with other atoms. For example, atoms of oxygen will react with atoms of hydrogen to form water (H2O). The number of protons in an atom's nucleus determines what element the atom is. For example, all atoms of carbon have 6 protons in their nucleus, so carbon is the element.