Physicists have filled in some longtime blank spaces on the periodic table, calculating electron affinities of the lanthanides, a series of 15 elements known as rare earths.

Here's what makes them so tricky. Electrons orbit in shells around an atom's nucleus, something like the layers of an onion, but in stranger shapes. Within each shell are a number of subshells.

Unusual filling of different sub-shells due to quantum confinement leads to a stable superatom that is also highly magnetic Industry uses magnetic materials in applications ranging from data ...