Final answer:
The model of the atom has evolved as scientific knowledge has advanced, moving from Dalton's indivisible particle to the current complex quantum mechanical model, which includes a central nucleus and electron probability clouds.
Step-by-step explanation:
The model of the atom has changed over time as scientific understanding has advanced. Initially, atoms were thought to be indivisible units as per Dalton's model. With the advent of new scientific experiments and discoveries, the model evolved significantly. For instance, Rutherford's gold foil experiment led to the realization that atoms have a dense, positively charged nucleus, contradicting the previously held plum pudding model.
Later on, Niels Bohr introduced the concept of electrons orbiting the nucleus in quantized shells, offering more insight into atomic structures and electron behavior. In the 20th century, quantum mechanics further refined the atomic model by introducing the concept of electron probability clouds, rather than fixed orbits. This helped to explain the unique spectral lines observed for each element, indicating that electrons occupy distinct energy levels.
Overall, the model of the atom has shifted from solid, indivisible particles to complex structures with a central nucleus and probability-based electron distributions, underscoring the iterative nature of the scientific method and the role of evidence in shaping our understanding.