Final answer:
The sequence of atomic models includes Dalton's indivisible spheres, Thomson's plum pudding model, Rutherford's nuclear model introducing the atomic nucleus, and Bohr's quantum model for hydrogen explaining atomic spectra. Rutherford's model was the first to suggest a nucleus following his gold foil experiment.
Step-by-step explanation:
The development of atomic models began with John Dalton, who envisioned atoms as indivisible spheres. Then came J. J. Thomson's model, where the atom was depicted as a plum pudding, with electrons embedded in a positively charged 'pudding.' The idea of the nucleus was introduced by Ernest Rutherford, whose gold foil experiment revealed that atoms consist of a tiny, dense, positively charged nucleus surrounded by electrons.
Niels Bohr built upon Rutherford's model, proposing that electrons move in specific orbits around the nucleus. Bohr's model, applied to the hydrogen atom, included three key postulates: (1) electrons move in circular orbits, (2) their angular momentum is quantized, and (3) electron transitions between orbits involve the emission or absorption of a photon. This model explained the atomic spectrum of hydrogen and established principles in quantum mechanics.
Significant Models of the Atom:
- John Dalton's model: Atoms as indivisible spheres
- J. J. Thomson's plum pudding model: Electrons embedded in a 'pudding' of positive charge
- Ernest Rutherford's nuclear model: Atoms have a dense, positively charged nucleus
- Niels Bohr's quantum model: Electrons move in quantized orbits around the nucleus
Rutherford's model was the first to propose a nucleus, revolutionizing our understanding of atomic structure. Subsequent models have sought to address questions such as why the nucleus does not fall apart and how to integrate the presence of protons with the stability of atoms.