Q.Write pairs of isotones and one pair of mirror nuclei from the following:
10-5-B, 12-6-C, 27-13-Al, 11-6-C, 28-14-Si

Step 1. Compute the neutron number N = A - Z for each of the five given nuclides: 10-5-B → N = 10-5 = 5. 12-6-C → N = 12-6 = 6. 27-13-Al → N = 27-13 = 14. 11-6-C → N = 11-6 = 5. The fifth entry is printed in the source as 'S: 28 14' -- since sulfur has Z=16 (not 14), while silicon has Z=14 exactly matching the printed subscript, this is read as silicon-28 (28-14-Si), a probable OCR/extraction artifact ('Si' misread as 'S:') disclosed here rather than silently assumed; N = 28-14 = 14.

Step 2. Group by matching N: N=5 gives the pair 10-5-B and 11-6-C (isotones -- different Z, same N, different A). N=14 gives the pair 27-13-Al and 28-14-Si (isotones -- different Z, same N, different A). N=6 (12-6-C) has no partner in this list. …

Compute N = A - Z for each nuclide, group any that share the same N as isotone pairs, then check for a same-A …

• Missing that mirror nuclei require identical A (not just similar proton/neutron counts), and forcing an incorrect 'mirror' pairing that doesn't actually satisfy the definition. …