How many letters does the top answer for “chemical process in which one atom or ion or group changes places with another” have?

The most common answer is exchange (8 letters).

Crossword clue: chemical process in which one atom or ion or group changes places with another

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

exchange 8 letters wn-def

chemical process in which one atom or ion or group changes places with another