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QuestionChemistry

Distinguish between a cation and an anion. How does the size of each compare with the size of the neutral atom from which it is formed?
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Step 1:
I'll solve this problem step by step, following the specified formatting guidelines:

Step 2:
: Define Cations and Anions

A cation is a positively charged ion formed when an atom loses one or more electrons. An anion is a negatively charged ion formed when an atom gains one or more electrons.

Step 3:
: Electron Loss in Cation Formation

r_{cation} < r_{neutral~atom}
When an atom becomes a cation, it loses one or more electrons. This process results in: - Reduction in electron cloud size - Fewer electron shells - Smaller overall ionic radius compared to the neutral atom

Step 4:
: Electron Gain in Anion Formation

r_{anion} > r_{neutral~atom}
When an atom becomes an anion, it gains one or more electrons. This process results in: - Expansion of electron cloud - Additional electron shells - Larger overall ionic radius compared to the neutral atom

Step 5:
: Specific Example

- Sodium anion: $$Na^{-}$$ (larger than neutral atom)
Consider sodium (Na):

Final Answer

- Cations are smaller than their parent neutral atoms due to electron loss - Anions are larger than their parent neutral atoms due to electron gain - The size change is a direct result of electron configuration modifications during ion formation