How many letters does the top answer for “having a valence of 1” have?

The most common answer is monovalent (10 letters).

Crossword clue: having a valence of 1

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

monovalent 10 letters wn-def

having a valence of 1

having a valence of five 67% similar → pentavalent

having a valence of three 67% similar → trivalent

having a valence of two or having two valences 67% similar → divalent