If you pass white light through a gas sample of an element and then look at the light through a spectroscope afterwards, you will see wavelengths missing from the white light, exactly matching the emission spectrum. This is called the Absorption Spectrum for that element. Like the emission spectrum, the absorption spectrum will always be the same. Chemists needed to be able to explain this reproducibility of spectra and Rutherford’s Nuclear Model did not do so.

Also, chemical behavior of elements is reproducible and Rutherford’s Model did not explain this either. A Danish Physicist, named Niels Bohr, in 1911 proposed a model for the atom, that preserved Rutherford’s Nucleus, but realized that the electron arrangement could not be random.(Because, by that time, chemists realized that chemical and spectral behavior was caused by the electrons, not the nucleus. Therefore, there had to be a reproducible pattern for the arrangement of the electrons.