Answer:
Total number of atoms in glucose are 24.
Step-by-step explanation:
 Photosynthesis: 
It is the process in which in the presence of sun light and chlorophyll by using carbon dioxide and water plants produce the oxygen and glucose. 
Carbon dioxide + water + energy → glucose + oxygen 
water is supplied through the roots, carbon dioxide collected through stomata and sun light is capture by chloroplast. 
Chemical equation: 
6H₂O + 6CO₂ + energy → C₆H₁₂O₆ + 6O₂ 
Glucose molecule = C₆H₁₂O₆ 
Total number of atoms = 6+12+6 = 24
Types of atoms = 3 (C,H,O)