Physics

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

\text{Mg}^{2+}

ions farther apart while leaving all other ions in place to lessen the repulsive force between them. b) Substitute half of the

\text{Mg}^{2+}

ions with

\text{Na}^{+}

ions to lower the magnitude of like-charge repulsion. c) Alternate

\text{Mg}^{2+}

and

\text{O}^{2-}

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.

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