Question: What is the cation with the highest isospin quantum number?
Paraphrase: What is the cation with the highest quantity of isospin?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q326277 . ?ent wdt:P1126 ?obj } ORDER BY DESC(?obj)LIMIT 5 
Answer: triton, deuteron