Why has the atomic model changed over time

there were two major atomic models, Bohr's and Rutherford's. The model changed over time with discoveries of electrons, protons, neutrons, orbitals etc.

In 1913 Bohr proposed his quantized shell model of the molecule to clarify how electrons can have stable circles around the core.  Radiation can happen just when the electron hops starting with one circle then onto the next

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

pie chart because it is in percents ( % )