The question asks to identify the scientist who proposed the plum pudding model of the atom. This requires knowledge of the historical development of atomic models and the contributions of key scientists.
D) J.J. Thomson — J.J. Thomson proposed the plum pudding model of the atom in 1904. This model depicted the atom as a sphere of positive charge with electrons embedded in it.
The question asks to identify the scientist credited with the discovery of the atomic nucleus. This requires knowledge of the history of atomic models and key experiments.
Correct Option: C) Ernest Rutherford is credited with the discovery of the nucleus through his famous gold foil experiment in 1911. His model proposed that an atom consists of a small, dense, positively charged nucleus around which electrons revolve.
The question asks to identify the scientist credited with the discovery of the neutron. This is a fundamental concept in atomic structure and requires knowledge of the history of atomic theory.
D) James Chadwick discovered the neutron in 1932 through his experiments involving the bombardment of beryllium with alpha particles.
The question asks for the approximate charge on an electron. This is a fundamental constant in physics and chemistry that candidates preparing for competitive exams are expected to know. We need to recall the standard value of the elementary charge and its sign for an electron.
C) The charge on an electron is approximately \(-1.6 \times 10^{-19}\) C. This value represents the elementary charge, which is a fundamental physical constant.
This question tests fundamental knowledge of the approximate mass of subatomic particles, specifically the proton. Candidates are expected to recall standard physical constants.
D) The mass of a proton is approximately \(1.67 \times 10^{-27}\) kg. This value is a fundamental constant in physics and chemistry.
The question asks about the definition of an atomic number. To answer this, we need to recall the fundamental components of an atom and how the atomic number is defined in chemistry and physics.
Therefore, the atomic number directly represents the number of protons in an atom's nucleus.
Correct Option: D) Number of protons