Answer
The answer is Cerium. Jöns Jakob Berzelius, a renowned Swedish chemist, made significant contributions to the field of chemistry in the early 19th century. Among his notable achievements was the discovery of several new elements, including Cerium. Cerium, belonging to the group known as lanthanides, is a rare earth metal valued for its unique properties and applications in various industries, including catalysis, metallurgy, and ceramics.