A student sketches a particulate model for MgO(s) in which two Mg²⁺ ions are drawn…
PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A student sketches a particulate model for MgO(s) in which two Mg²⁺ ions are drawn adjacent to each other, with O²⁻ ions placed at greater separations. Which modification would make the model most consistent with Coulomb’s law?
(a) Move the two adjacent Mg2+ ions farther apart while leaving all other ions in place to lessen the repulsive force between them.
(b) Substitute half of the Mg2+ ions with Na+ ions to lower the magnitude of like-charge repulsion.
(c) Alternate Mg2+ and O2− ions so that no like-charged ions are nearest neighbors.
(d) Compress the entire array so that every ion is closer to its oppositely charged neighbors, increasing the overall attractive forces.