Number of elements from the following that CANNOT form compounds with valencies which match with their respective group valencies is .

B, C, N, S, O, F, P, Al, Si

Question

Number of elements from the following that CANNOT form compounds with valencies which match with their respective group valencies is .

B, C, N, S, O, F, P, Al, Si

Canvas Classes · Accepted Answer

Strategy:
 Second-period elements like Oxygen (O) and Fluorine (F) lack -orbitals in their valence shell. This restricts them from expanding their octet to match their group valency (e.g., Fluorine cannot show a valency of 7).

Step 1: Identify group valencies
- Group 13 (Al, B): 3
- Group 14 (Si, C): 4
- Group 15 (P, N): 5
- Group 16 (S, O): 6
- Group 17 (F): 7

Step 2: Evaluate octet expansion
- Elements from Period 3 onwards (Al, Si, P, S) can expand their octet using empty -orbitals.
- Eleme

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