In this video excerpt from NOVA's "Hunting the Elements," New York Times technology columnist David Pogue examines how atomic structure determines reactivity. Meet Theo Gray, chemist and author, who ...

The distribution of outermost shell electrons, known as valence electrons, of organic molecules was observed for the first time. As the interactions between atoms are governed by the valence electrons ...

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 ...