Q. Who discovered plutonium and co-developed the actinide concept?
Answer:
Glenn T. Seaborg
Notes: Glenn T. Seaborg co-discovered plutonium in 1940 and introduced the actinide concept, reorganizing the periodic table. He was awarded the Nobel Prize in Chemistry (1951). Element 106, seaborgium, is named in his honor—a rare distinction during a scientist's lifetime.