Multiple choice general knowledge science & technology Chlorophyll is a naturally occurring chelate compound in which central metal is copper iron magnesium calcium Reveal answer Fill a bubble to check yourself C Correct answer Explanation Chlorophyll's porphyrin ring contains a magnesium ion (Mg2+) at its center, which is essential for photosynthesis. Iron is the central metal in heme (hemoglobin), while copper and calcium are not involved in chlorophyll structure.