The krakato eruption destroyed life and left behind volcanic ash. a large chemical spill can also destroy life. how would succession be very different following these two events?

Since chemical spills are very harmful to aquatic/land life for both plants and animals, plants probably wouldn't grow back and animals could be mutated or even killed, decreasing the population of that species. A volcano eruption, can be both good and bad, since a volcano can kill animals and plants, but ash from a volcano is extremely fertile, so plants can regrow, which in turn brings animals back so they can feed on those plants.

allowed for the prediction of the properties of missing elements.