Question

which experiment led to the idea that atoms contain a small and dense positive charge or nucleus inside of them?
daltons gas experiments
rutherfords gold foil experiment
bohrs light emission experiments
thomsons cathode ray experiments

Explanation:

Dalton's experiments established atomic theory but not the nucleus. Thomson's cathode ray experiments discovered electrons, leading to the "plum pudding" model. Bohr's work focused on electron energy levels. Rutherford's gold foil experiment, where alpha particles were deflected by a dense positive core, provided evidence for the atomic nucleus.

Answer:

Rutherford's gold foil experiment