Why does `H^+` ion always get associated with other atoms or molecules?

Options

A. Ionisation enthalpy of hydrogen resembles that of alkali metals
B. Its receptivity is similar to halogens
C. It resembles both alkali metals and halogens
D. None of the above

Answer

To understand why the `H^+` ion (proton) always gets associated with other atoms or molecules, we can break down the explanation into several steps:

### Step 1: Understanding the Structure of Hydrogen
- Hydrogen has an atomic number of 1, which means it has one proton and one electron. Its electronic configuration is 1s¹.
- When hydrogen loses its electron, it forms a `H^+` ion, which consists solely of a proton.

### Step 2: Characteristics of the `H^+` Ion
- The `H^+` ion is essentially a bare proton, which is very small in size and has a high positive charge.
- Due to its small size and high charge density, the `H^+` ion has a strong tendency to attract electrons from nearby atoms or molecules.

### Step 3: Stability Considerations
- Free protons are not stable in solution or in the gas phase because they lack the surrounding electron cloud that stabilizes other ions.
- To achieve stability, the `H^+` ion readily associates with other atoms or molecules, forming bonds. This association often leads to the formation of hydronium ions (`H₃O^+`) in aqueous solutions.

### Step 4: Conclusion
- The `H^+` ion cannot exist freely due to its small size and high charge density, which leads it to seek stability by associating with other atoms or molecules.

### Final Answer
The `H^+` ion always gets associated with other atoms or molecules because it is a bare proton that is highly reactive and unstable in isolation. Its small size and high positive charge make it unable to exist freely, thus it forms bonds with other species to achieve stability.

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