A British physicist, Ernest Rutherford , took giant steps forwarder in the study of atoms, when he named, and described may aspects of radioactivity.
Rutherford worked on radioactivity and coined the terms ‘alpha’ and ‘beta’ to describe the two different types of radiation.
He also observed that radioactive material took the same amount of time for half of it to decay, and called this ‘half-life’ of the material.
Most significantly, in 1911, Rutherford created a model of the atom that was simplified in a well known symbol. It showed electrons circling around the nucleus, like planets orbiting the sun.