This question tests fundamental knowledge about the properties of subatomic particles, specifically the mass of a neutron. It requires recalling the standard value for the mass of a neutron in kilograms.
Correct Option: A) \(1.6749 \times 10^{-27} \text{ kg}\) is the correct approximate mass of a neutron.
The question asks for the charge on a proton. This is a fundamental constant in physics and chemistry. We need to recall the magnitude and sign of the elementary charge and apply it to a proton.
Correct Option: B) +1.602 × 10^-19 C
The question asks for the alternative name of Thomson's model of an atom. This requires recalling the historical models of the atom and their common names.
Correct Option: B) Plum pudding model — Thomson's model envisioned the atom as a sphere of positive charge with electrons embedded in it, similar to plums in a pudding, hence the name.
The question asks about the material used as a thin foil in Rutherford's alpha-particle scattering experiment. This experiment was crucial in understanding the structure of the atom. The choice of material was important for the success and interpretation of the experiment.
C) Gold — Rutherford's alpha-particle scattering experiment famously used a thin gold foil due to gold's high malleability (allowing it to be made extremely thin) and high atomic number (providing a strong positive charge for effective scattering of alpha particles).
The question asks for the major conclusion drawn from Rutherford's gold foil experiment. This experiment, also known as the Geiger-Marsden experiment, involved firing alpha particles at a thin sheet of gold foil. The observations from this experiment led to a revolutionary understanding of atomic structure.
B) Most of the atom is empty space with a dense positive nucleus. This directly aligns with Rutherford's conclusions from the gold foil experiment, explaining why most alpha particles passed through and why some were deflected at large angles.
The question asks to identify a major drawback of Rutherford's atomic model. We need to recall the postulates and limitations of Rutherford's model and compare them with the given options.
A) It could not explain the stability of the atom
According to classical electromagnetic theory, an electron revolving in a circular orbit is an accelerating charged particle and should continuously radiate energy. As it loses energy, its orbit should continuously shrink, causing it to spiral into the nucleus. This would make the atom unstable and collapse, which is contrary to the observed stability of atoms. Rutherford's model offered no explanation for this inherent instability.