Following Ernest Rutherford's discovery of the atomic nucleus in the early 20th century, scientists were primarily trying to discern the arrangement and behavior of the electrons within an atom's structure. Rutherford's gold foil experiment in 1909 had shown that atoms were mostly empty space with a small, dense nucleus at the center. This discovery led to the realization that electrons must be orbiting the nucleus in some way.
To understand the atom's structure more completely, scientists were interested in:
The arrangement of electrons: They wanted to determine how electrons were distributed around the nucleus, their energy levels, and their orbits.
The nature of electron behavior: Scientists sought to understand how electrons move, how they interact with the nucleus and with each other, and how they emit or absorb energy in the form of light (spectral lines).
This period of scientific exploration ultimately led to the development of quantum mechanics and the Bohr model of the atom, which provided a framework for explaining the behavior of electrons in atoms. Later advancements in quantum theory provided a more accurate and comprehensive understanding of atomic structure.