In 1912 Bohr joined Rutherford. He realized that Rutherford's model wasn't quite right ... to the periodic repetition of properties of the elements. The shells in which electrons orbit have ...

In Bohr's model, if an electron orbit is not already filled, then it's easier for the atoms to exchange or share those electrons and induce chemical reactions. One class of elements, the noble ...

In 1913, Niels Bohr revised Rutherford's model by suggesting that the electrons ... must be the same for every single atom of that element. Therefore, electrons cannot be arranged at random ...

Most of the mass of an atom is found in the nucleus. 1913 Bohr In-depth work on Rutherford's model showed it had limitations. The electrons should just spiral in towards the positive nucleus.