Multiple choice general knowledge science & technology Chlorophyll is a naturally occurring chelate compound in which central metal is copper magnesium iron calcium Reveal answer Fill a bubble to check yourself B Correct answer Explanation Chlorophyll is a chelate compound where magnesium is the central metal ion, coordinated to a porphyrin ring. This is similar to heme in blood where iron is the central metal. Copper, iron, and calcium are not the central metal in chlorophyll.