Choose the correct statement(s):

Options

A. `H^(+)` is the smalest size cation in the periodic table.
B. van der waals' radius of chlorine is more than covalent radius
C. ionic mobility of hydrated `Li^(+)` is greater than that of hydrated `Na^(+)`.
D. He atom is having highest I.E. in the periodic state

Answer

To solve the question, we need to evaluate each statement provided and determine whether they are true or false. Let's analyze each statement step by step.

### Step 1: Evaluate the first statement
**Statement A:** "H⁺ is the smallest size cation in the periodic table."

- **Analysis:** The hydrogen ion (H⁺) is formed when hydrogen loses its only electron. Since it has no electrons, it is effectively just a proton, which means it has the smallest size among all cations. Other cations have more electrons and thus larger sizes due to increased electron-electron repulsion and additional electron shells.
- **Conclusion:** This statement is **True**.

### Step 2: Evaluate the second statement
**Statement B:** "Van der Waals radius of chlorine is more than covalent radius."

- **Analysis:** The Van der Waals radius refers to the size of an atom when it is not bonded to another atom, while the covalent radius is the size of an atom when it is bonded to another atom. In a covalent bond, the atoms overlap, which reduces the effective size compared to when they are not bonded. Therefore, the Van der Waals radius is indeed larger than the covalent radius.
- **Conclusion:** This statement is **True**.

### Step 3: Evaluate the third statement
**Statement C:** "Ionic mobility of hydrated lithium ion (Li⁺) is greater than that of hydrated sodium ion (Na⁺)."

- **Analysis:** Ionic mobility is inversely related to the size of the ion. Lithium ion (Li⁺) is smaller than sodium ion (Na⁺), which means Li⁺ will have a stronger interaction with water molecules and will form a more stable hydration shell. This results in lower mobility compared to Na⁺, which is larger and has a weaker interaction with water molecules. Therefore, the statement that Li⁺ has greater mobility than Na⁺ is incorrect.
- **Conclusion:** This statement is **False**.

### Step 4: Evaluate the fourth statement
**Statement D:** "Helium atom is having the highest ionization enthalpy in the respective period."

- **Analysis:** Helium has a complete electron configuration (1s²), making it very stable. The ionization enthalpy is the energy required to remove an electron from an atom. Since helium is the smallest atom with a filled outer shell, it has the highest ionization enthalpy among all elements in its period (the noble gases).
- **Conclusion:** This statement is **True**.

### Final Conclusion
Based on the evaluations:
- Statement A: True
- Statement B: True
- Statement C: False
- Statement D: True

Thus, the correct statements are A, B, and D.

### Summary of Correct Statements
The correct statements are:
- H⁺ is the smallest size cation in the periodic table (True).
- Van der Waals radius of chlorine is more than covalent radius (True).
- Helium atom is having the highest ionization enthalpy in the respective period (True).