STATEMENT-1 : The plot of atomic number ( -axis) versus number of neutrons ( -axis) for stable nuclei shows a curvature towards -axis from the line of slope as the atomic number is increased.
and
STATEMENT-2 : Proton-proton electrostatic repulsions begin to overcome attractive forces involving protons and neutrons in heavier nuclides.
and
STATEMENT-2 : Proton-proton electrostatic repulsions begin to overcome attractive forces involving protons and neutrons in heavier nuclides.
- (A)STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1✓ Correct
- (B)STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1
- (C)STATEMENT-1 is True, STATEMENT-2 is False
- (D)STATEMENT-1 is False, STATEMENT-2 is True
Answer: (A)
Solution
STATEMENT-1 is True: For light nuclei, the neutron-to-proton ratio is approximately 1:1 (45° line). As atomic number increases, stable nuclei require more neutrons than protons to counteract proton-proton repulsion, causing the plot to curve toward the x-axis (more neutrons).
STATEMENT-2 is True and is a correct explanation: In heavier nuclei, proton-proton electrostatic repulsions increase significantly. Additional neutrons are needed to provide extra nuclear binding force without adding more repulsive charge, stabilizing the nucleus.
Therefore, both statements are true and Statement-2 correctly explains Statement-1.
STATEMENT-2 is True and is a correct explanation: In heavier nuclei, proton-proton electrostatic repulsions increase significantly. Additional neutrons are needed to provide extra nuclear binding force without adding more repulsive charge, stabilizing the nucleus.
Therefore, both statements are true and Statement-2 correctly explains Statement-1.
JEE Advanced · 2008 · 13 Apr 2008 · Paper 1 · Single correct option