Which element in group 15 forms a pentoxide with the highest thermal stability?
Thermal stability of group 15 pentoxides (X₂O₅) decreases down the group due to weaker X-O bonds. N₂O₅ is the most stable thermally, decomposing at a higher temperature than P₂O₅, As₂O₅, or Sb₂O₅.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Modern Periodic Law and Present Form - Long Form Periodic Table