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. Physicists at Michigan ...

Electrons in atoms occupy energy levels, also called electron shells, outside the nucleus. Different shells can hold different maximum numbers of electrons. The electrons in an atom occupy the lowest ...

Elements in group 1 and group 2 are metals. Atoms of group 1 elements have one electron in their outer shell, and atoms of group 2 elements have two electrons in their outer shell. Elements in groups ...

RUN your fingers over the white keys of a piano. The notes get higher and higher as your hand moves to the right. On the eighth key, something beautiful happens: a note hangs in the air that embodies ...