What is the blast radius of a 500 pound bomb?

No. Those sizes may be the most common, but there are smaller bombs and larger ones. 1000-pound, 2000-pound, and 4000-pound bombs were used in WW2. Blockbuster bombs go up to 12,000 pounds. BLU-bombs weigh 15,000 pounds and were used in Nam. 20,000 pound bombs were used in WW2. There is a MOAB type bomb weighing 22,000 pounds but it has yet to be used. Earthquake bunker-busters have been developed (but apparently not yet used), weighing up to 43,600 pounds.