Atomic Theory: Scientists & Models

Democritus' atomic theory, while foundational, lacked a key element crucial to modern scientific theories. What was this missing element?

Dalton's Atomic Theory included several postulates that revolutionized the understanding of matter. Which of the following statements accurately reflects one of Dalton's key postulates?

J.J. Thomson's Cathode Ray Tube experiment was pivotal in disproving a key tenet of Dalton's Atomic Theory. Which statement best describes how Thomson's work challenged Dalton's model?

Rutherford's Gold Foil experiment led to a revolutionary model of the atom. What key observation from this experiment was most influential in concluding that atoms have a small, dense, positively charged nucleus?

While Rutherford's model was a significant advancement, it failed to explain certain phenomena related to electron behavior. What key question remained unanswered by the Nuclear Model?

Bohr's model introduced the concept of quantized energy levels for electrons. How did this concept explain the discrete spectral lines observed in hydrogen's emission spectrum?

Chadwick's discovery of the neutron resolved a crucial discrepancy in atomic masses. Which of the following best describes the problem Chadwick addressed?

Each atomic model contributed to a more complete understanding of atomic structure. Considering the progression from Dalton to Chadwick, what is a major conceptual difference between Dalton's model and Chadwick's model?

The Gold Foil experiment provided evidence that most of the atom is empty space. If alpha particles were fired at a screen of tightly packed bowling balls, what result would disprove the conclusion of the Gold Foil experiment?

Both Thomson and Rutherford proposed models involving charged particles within the atom. What is the most significant difference between their models' arrangement of positive and negative charges?

Bohr's model accounted for the specific wavelengths of light emitted by excited hydrogen atoms. If an atom had 4 possible electron orbits, how many potential wavelengths of light could it emit?

Chadwick's discovery of the neutron had implications beyond just correcting atomic mass calculations. Which of the following was a DIRECT consequence of this discovery?

Consider the historical progression of atomic models. What fundamental assumption, present in Dalton's model, was challenged by BOTH Thomson's and Rutherford's experiments?

Suppose you are asked to design a new experiment that would test a prediction made by Bohr's model, but not by Rutherford's. What is one hypothesis of Bohr's model that is NOT present in Rutherford's?

If an element was discovered that emitted a continuous spectrum of light (all wavelengths), which statement would reflect the theoretical implications of that discovery?

Imagine performing the Gold Foil experiment using a radioactive material that emits only electrons instead of alpha particles. What result would be MOST likely?

How did Chadwick's discovery explain the existence of isotopes (atoms of the same element with different masses)?

If Rutherford had used a thicker gold foil in his experiment, how might the results and his subsequent conclusions be different?

Consider a hypothetical element which, when heated, emits only two distinct wavelengths of light. Based on Bohr's model, what can you infer about that element?

How would the observed behavior of electrons in Thomson's Plum Pudding model differ from that in Rutherford's Nuclear model if an external electric field were applied?