Bohr's model of the hydrogen atom provides a foundational understanding of electron energy levels, accurately predicting the differences between energy levels corresponding to transitions between principal quantum numbers. Initially developed in the early 20th century, the model's predictions were confirmed through experimental data, particularly in the context of hydrogen. However, as spectroscopy techniques advanced, discrepancies emerged, notably with phenomena such as the Zeeman effect, anomalous Zeeman effect, hyperfine structure, and the Lamb shift, which the Bohr model could not adequately explain. While Bohr's rules effectively predicted energy levels for hydrogen, they fell short for more complex atoms, highlighting the model's limitations. Overall, Bohr's contributions remain significant, but further developments in quantum mechanics have provided a more comprehensive understanding of atomic behavior.