Questions: Consider the A atom and the A^2- ion. Which will have the larger radius? Multiple Choice the A^2- anion the A^2- cation the A atom They will both have identical radii. Cannot be determined from the information provided.

Consider the A atom and the A^2- ion. Which will have the larger radius?

Multiple Choice
the A^2- anion
the A^2- cation
the A atom
They will both have identical radii.
Cannot be determined from the information provided.

Transcript text: Consider the A atom and the $\mathrm{A}^{2}$ - ion. Which will have the larger radius? Multiple Choice the $A^{2}$-anion the $A^{2}$ - cation the $A$ atom They will both have identical radii. Cannot be determined from the information provided.

Solution

Solution Steps

Step 1: Understanding Atomic and Ionic Radii

The radius of an atom or ion is influenced by the number of electrons and the effective nuclear charge. When an atom gains electrons to form an anion, the added electrons increase electron-electron repulsion, causing the electron cloud to expand and the radius to increase. Conversely, when an atom loses electrons to form a cation, the reduced electron-electron repulsion and increased effective nuclear charge cause the electron cloud to contract, resulting in a smaller radius.

Step 2: Comparing the A Atom and the $\mathrm{A}^{2-}$ Ion

Given the options, we need to compare the radius of the neutral atom $A$ and the anion $\mathrm{A}^{2-}$. The $\mathrm{A}^{2-}$ ion has gained two additional electrons compared to the neutral atom $A$, which increases the electron-electron repulsion and causes the radius to expand.