One reason some metals have toxic effects is that they can replace other metals in a biomolecule and thereby inhibit or destroy the function of the biomolecule. Such replacement depends on the charge and size of the metal ion. For each of the following pairs of metal ions, identify the one that is larger.
(Ca²⁺, Mg²⁺)
(Ca²⁺, Zn²⁺)
(P³⁺, As³⁺)

Question

Quizplus · Accepted Answer

In each pair, the metal ion with the larger atomic number (i.e. further down the periodic table) will typically have a larger size. Therefore, the larger ion in each pair is: Ca²⁺, Ca²⁺, and As³⁺. Only choice B correctly identifies which ion is larger in each pair.

One Reason Some Metals Have Toxic Effects Is That They