Final answer:
Cations are smaller than neutral atoms, while anions are larger. The size difference is due to the gain or loss of electrons. Visual representations of ions as spheres can help convey the size difference.
Step-by-step explanation:
Cations are always smaller than the neutral atom, while anions are always larger. The size difference between cations and neutral atoms is due to the loss of one or more electrons, resulting in a decrease in electron-electron repulsion and a smaller atomic radius. An example of a cation is the potassium ion (K+), which has lost one electron and has a +1 charge. On the other hand, an example of an anion is the chloride ion (Cl-), which has gained one electron and has a -1 charge.
The size of ions can also vary depending on their oxidation states. For example, sodium ion (Na+) is larger than the neutral sodium atom because the additional electron in the ion produces a 3s² valence electron configuration, while the nuclear charge remains the same. However, the Nation ion, which has lost one electron, is significantly smaller than the neutral sodium atom because the 3s¹ electron has been removed.
In general, cations are represented by smaller spheres, while anions are represented by larger spheres when drawing ionic compounds. This visual representation helps to convey the size difference between cations and anions.