Long puzzling scientists, a new study examined why magnets will hold themselves to all sorts of metal except plutonium.

According to Live Science, authors of a study published in the journal Science Advances found the answer to be within the metal's electrons. Unlike other metals, plutonium atoms do not have a fixed amount of electrons spinning around its outer shell.

"Plutonium sort of exists between two extremes in its electronic configuration-in what we call a quantum mechanical superposition," study lead author Marc Janoschek, of the Los Alamos National Laboratory, said in a press release. "Think of the one extreme where the electrons are completely localized around the plutonium ion, which leads to a magnetic moment. But then the electrons go to the other extreme where they become delocalized and are no longer associated with the same ion anymore."

Plutonium atoms were found to have between four and six electrons in ground state, which occurs when no outer source of energy is applied to the atom. Janoschek told Live Science the plutonium atom " fluctuates between three different configurations."

That means the electrons in magnets can never find a match in plutonium, because the metal's electrons are constantly changing.

"We used a special method developed at Los Alamos to remove the hydrogen from our sample," Janoschek said in the release. "Many people across our laboratory and the complex helped solve these problems, but I'm especially grateful to Eric Bauer, Capability Leader for Materials Synthesis and Characterization in the Condensed Matter and Magnet Science group at Los Alamos, for helping me design a successful experiment."