The concept of the nuclear atom, where a positively charged nucleus is surrounded by negatively charged electrons, is attributed to Ernest Rutherford.

Here's a breakdown of his key contributions:

* Gold Foil Experiment (1911): Rutherford's famous experiment, where alpha particles were fired at a thin gold foil, showed that most particles passed through, but a few were deflected at large angles. This led him to propose that atoms have a small, dense, positively charged nucleus at their center, with the electrons orbiting around it.

While Rutherford's model was a significant step forward, it was later refined by Niels Bohr, who introduced the concept of quantized energy levels for electrons orbiting the nucleus.

So, while Rutherford is credited with the foundational discovery of the nuclear atom, the model itself evolved over time with contributions from other scientists.