-Current knowledge atom comprises an atomic nucleus, in which almost all of its mass, surrounded by a cloud of electrons is concentrated.
-Atoms are classified according to the number of protons and neutrons in its nucleus containing.
-The number of protons or atomic number determines their chemical element.
-An atom with the same number of protons and electrons is electrically neutral. If instead possesses an excess of protons or electrons, the charge is positive or negative.
