Rutherford's alpha-particle scattering experiment, also known as the gold foil experiment, was a landmark experiment that led to the discovery of the atomic nucleus. The observations from this experiment provided crucial insights into the structure of the atom, disproving J.J. Thomson's plum pudding model.
A) (1) Most alpha particles passed straight through (2) Some were deflected by small angles (3) One in every 12,000 particles bounced back. This option accurately lists the three key observations made during Rutherford's alpha-particle scattering experiment.
Rutherford's alpha-particle scattering experiment, also known as the Geiger-Marsden experiment, provided crucial insights into the structure of the atom. By observing how alpha particles interacted with a thin gold foil, Rutherford deduced the presence and characteristics of the atomic nucleus.
Correct Option: B) The atom has a tiny, dense, positively charged nucleus that contains all the positive charge and most of the mass of the atom
The question asks about the limitations of Rutherford's atomic model. We need to evaluate each option based on our understanding of Rutherford's model and its subsequent refinements.
Correct Option: C) It could not explain the stability of the atom — electrons revolving in circular orbits would continuously radiate energy, slow down, spiral inward and collapse into the nucleus
This option accurately describes the primary limitation of Rutherford's model. According to classical electrodynamics, an electron moving in a circular orbit is an accelerating charge and should continuously emit electromagnetic radiation. This loss of energy would cause the electron to spiral into the nucleus, making the atom unstable. However, atoms are stable, which Rutherford's model failed to explain.
The question asks about Rutherford's model of the atom, specifically concerning the position and movement of electrons. We need to recall the key postulates of Rutherford's atomic model, which was based on his famous alpha-particle scattering experiment.
D) Electrons revolve around the nucleus in circular orbits at high speed, and the electrostatic attraction of the nucleus balances the centrifugal force. This statement accurately describes Rutherford's proposal regarding the electrons in his atomic model. He envisioned electrons orbiting the nucleus much like planets orbit the sun, with the electrostatic force providing the necessary centripetal force.
The question asks about Rutherford's model of the atom. We need to recall the key findings and conclusions drawn from Rutherford's alpha-particle scattering experiment, which led to his atomic model.
A) Empty space (the electrons orbit at relatively large distances from the nucleus) — This statement accurately reflects Rutherford's model, where the vast majority of the atom is empty space, with electrons orbiting a tiny, dense nucleus.
The question asks for the year Bohr's model was proposed and the specific limitation of Rutherford's model it addressed. We need to recall the historical development of atomic models and their key features and limitations.
D) 1913; Bohr resolved the stability problem by proposing that electrons revolve in fixed orbits of definite energy (stationary states) without radiating energy — This option correctly states the year Bohr's model was proposed (1913) and accurately describes how it resolved the major limitation of Rutherford's model, which was the instability of the atom due to continuous energy radiation by orbiting electrons.