`{:(1."Arrangement of electrons in energy shells", a."Valence shell"),(2."Maximum number of electrons = 18",b."Electronic configuration"),(3."Outermost shell of an atom",c."Valency"),(4."Combining cpacity of the atoms of an element",d."Number of charge it carries"),(5."An element with 8 valence electrons",e."M energy shell"),(6."Valency of a radical",f."Octet configuration"):}`

Answer

To solve the matching question, we need to connect the items in Column 1 with the appropriate items in Column 2. Let's go through each point step by step.

### Step-by-Step Solution:

1. **Arrangement of electrons in energy shells**:
- The arrangement of electrons in energy shells is referred to as **Electronic Configuration**.
- **Match**: 1 → B

2. **Maximum number of electrons = 18**:
- The maximum number of electrons that can be accommodated in the M energy shell is 18.
- **Match**: 2 → E

3. **Outermost shell of an atom**:
- The outermost shell of an atom is known as the **Valence Shell**.
- **Match**: 3 → A

4. **Combining capacity of the atoms of an element**:
- The combining capacity of the atoms of an element is termed as **Valency**.
- **Match**: 4 → C

5. **An element with 8 valence electrons**:
- An element that has 8 valence electrons follows the **Octet Configuration**.
- **Match**: 5 → F

6. **Valency of a radical**:
- The valency of a radical is equal to the **number of charges it carries**.
- **Match**: 6 → D

### Final Matches:
- 1 → B (Electronic Configuration)
- 2 → E (M energy shell)
- 3 → A (Valence Shell)
- 4 → C (Valency)
- 5 → F (Octet Configuration)
- 6 → D (Charge it carries)