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Question 1:

Who proposed the plum pudding model of the atom?

A) J.J. Thomson
B) Ernest Rutherford
C) Niels Bohr
D) James Chadwick

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Explanation: The correct answer is A) J.J. Thomson. J.J. Thomson proposed the plum pudding model of the atom in 1904. According to this model, atoms are composed of a positively charged "pudding" with negatively charged electrons embedded within it.

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Question 2:

Who conducted the gold foil experiment, leading to the discovery of the atomic nucleus?

A) J.J. Thomson
B) Ernest Rutherford
C) Niels Bohr
D) James Chadwick

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Explanation: The correct answer is B) Ernest Rutherford. Ernest Rutherford conducted the gold foil experiment in 1911. The experiment involved bombarding a thin sheet of gold foil with alpha particles, which led to the discovery of the atomic nucleus and the understanding that most of the atom's mass is concentrated in a small, dense region at its center.

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Question 3:

According to Bohr's model of the atom, electrons:

A) Move in random paths around the nucleus
B) Occupy fixed energy levels or orbits
C) Are found in the nucleus
D) Have wave-like properties only

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Explanation: The correct answer is B) Occupy fixed energy levels or orbits. According to Bohr's model of the atom, electrons exist in fixed energy levels or orbits around the nucleus. These energy levels are quantized, and electrons can jump between energy levels by gaining or losing energy.

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Question 4:

Who proposed the quantum mechanical model of the atom?

A) J.J. Thomson
B) Ernest Rutherford
C) Niels Bohr
D) Erwin Schrödinger

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Explanation: The correct answer is D) Erwin Schrödinger. Erwin Schrödinger proposed the quantum mechanical model of the atom in 1926. This model describes the behavior of electrons as wave-like entities and uses mathematical equations known as wave functions to determine the probability distribution of finding an electron in a particular region around the nucleus.

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Question 5:

According to the quantum mechanical model, an atomic orbital is:

A) A circular path followed by an electron
B) The exact position of an electron in an atom
C) A region in space with a high probability of finding an electron
D) The positively charged center of an atom

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Explanation: The correct answer is C) A region in space with a high probability of finding an electron. According to the quantum mechanical model, an atomic orbital represents a region in space where there is a high probability of finding an electron. Orbitals are characterized by their shape, size, and energy.