Match the elements given in Column I with the properties mentioned in Column II.
`{:(Column I,Column II),(A.Li,1."Insoluble sulphate"),(B.Na,2."Strongest monoacidic base"),(C.Ca,3."Most negative" E^(Theta) "value among alkali metals"),(D.Ba,4."Insoluble oxalate"),(,5.6s^(2)"outer electronic configuration"):}`

Explanation

To match the elements from Column I with the properties in Column II, we can analyze each element and its corresponding property step by step.

### Step-by-Step Solution:

1. **Element A: Lithium (Li)**
- Lithium has the most negative standard electrode potential (E°) value among alkali metals due to its high hydration energy. This high hydration energy compensates for its ionization energy, making it a strong reducing agent.
- **Match:** A → 3 ("Most negative" E° value among alkali metals)

2. **Element B: Sodium (Na)**
- Sodium is known to form the strongest monoacidic base. A monoacidic base releases one hydroxide ion (OH⁻) in solution. Sodium hydroxide (NaOH) is a strong base, and compared to lithium, which has covalent character, sodium is the strongest among the alkali metals.
- **Match:** B → 2 ("Strongest monoacidic base")

3. **Element C: Calcium (Ca)**
- Calcium oxalate (CaC₂O₄) is known to be insoluble in water. This property is significant as it is often associated with kidney stones.
- **Match:** C → 4 ("Insoluble oxalate")

4. **Element D: Barium (Ba)**
- Barium has an outer electronic configuration of 6s², and it also forms an insoluble sulfate (BaSO₄) due to its low hydration energy, which prevents it from dissolving in water.
- **Match:** D → 1 ("Insoluble sulfate") and D → 5 (6s² outer electronic configuration)

### Final Matches:
- A → 3
- B → 2
- C → 4
- D → 1 and 5