jan 1, 1907 - Ernest Rutherford

Description:

Inspired, Rutherford continued investigating radioactivity to find that atoms emit "Alpha & Beta rays" when decaying from a heavier to lighter atom. To further advance and solidify his findings he conducted the "Gold foil" experiment, where he directed alpha rays and atoms towards gold and observed that there was minor resistance when passing through. What this led to was the discovery that atoms were mostly "empty", lacking protons/neutrons/electrons. Just a positively charged nucleus and electrons. This influenced the perception of the atomic model.

There is also a third type of radiation/decay. Gamma rays emit an intense wave which can go through practically everything--including our bodies. It takes two cm of lead or a meter of concrete to be stopped.

It should also be mentioned that these forms of radiation occur in the first place due to unstable isotopes.