Which of the following best describes how our modern understanding of atomic structure differs from Thomson's plum pudding model?

• A. The modern model suggests that atoms are indivisible particles, while Thomson's model allowed for the existence of subatomic particles.
• B. The modern model states that atoms do not contain any charged particles, whereas Thomson's model included both positive and negative charges.
• C. The modern model proposes that atoms are made only of electrons, while Thomson's model included both electrons and protons.
• D. The modern model describes the atom as having a dense, positively charged nucleus with electrons orbiting around it, whereas Thomson's model depicted electrons embedded in a uniform positive sphere.

Answer: (D)

Verified step by step guidance

1. Recall Thomson's plum pudding model: it proposed that the atom is a uniform, positively charged sphere with negatively charged electrons embedded within it, like 'plums' in a 'pudding'.
2. Understand the modern atomic model: it describes the atom as having a small, dense, positively charged nucleus at the center, with electrons orbiting around this nucleus in defined regions.
3. Compare the two models by focusing on the distribution of positive charge: Thomson's model spreads positive charge uniformly throughout the atom, while the modern model concentrates it in the nucleus.
4. Note the arrangement of electrons: in Thomson's model, electrons are fixed within the positive sphere, whereas in the modern model, electrons move around the nucleus in orbitals or energy levels.
5. Summarize the key difference: the modern atomic model introduces the concept of a nucleus and electron orbits, replacing the idea of a uniform positive sphere with embedded electrons.