The question asks to identify the scientist who discovered neutrons and the year of discovery, along with the experimental method used. This requires knowledge of fundamental atomic structure discoveries.
A) James Chadwick, 1932, by bombarding beryllium with alpha particles — This option correctly identifies James Chadwick as the discoverer of the neutron, the year 1932, and the experimental method used (bombarding beryllium with alpha particles).
The question asks for the correct description and properties of a neutron. We need to evaluate each option based on our knowledge of atomic structure and sub-atomic particles.
C) A neutron is an electrically neutral (uncharged) sub-atomic particle present in the nucleus of all atoms except ordinary hydrogen; its mass is approximately equal to that of a proton.
The question asks to identify the correct description of J.J. Thomson's atomic model. We need to recall the key features of Thomson's model and compare them with the given options.
Correct Option: A) An atom is a sphere of uniform positive charge with electrons embedded in it like raisins in a pudding (plum pudding model)
The question asks about Thomson's model of the atom and how it explained electrical neutrality. We need to recall the key features of Thomson's model, often called the "plum pudding" model, and how it addressed the overall charge of an atom.
Correct Option: B) The positive charge of the sphere and the negative charge of the embedded electrons are equal in magnitude, so they cancel each other, making the atom neutral
This option accurately describes how Thomson's model explained the electrical neutrality of the atom. The model posited a balance between the distributed positive charge and the discrete negative charges.
The question asks about the limitations of Thomson's Model of the atom. We need to identify the reasons why this model was eventually discarded or found to be inadequate.
This option accurately lists the major limitations of Thomson's model. It could not explain the experimental observations of Rutherford's alpha-particle scattering experiment, which led to the discovery of the atomic nucleus. Consequently, Thomson's model did not incorporate a nucleus. Furthermore, it failed to explain the characteristic line spectra emitted by atoms.
The question asks about the specific material used by Rutherford in his famous alpha-particle scattering experiment, which led to the discovery of the atomic nucleus. This is a direct recall question related to a foundational experiment in atomic physics.
A) Gold foil (a very thin sheet of gold, approximately 1000 atoms thick) is the correct answer. Rutherford's experiment famously used a thin gold foil because gold is highly malleable and could be made into an extremely thin sheet, which was crucial for the experiment to observe the scattering of alpha particles.