Electron–hole exchange interaction is an intrinsic property of semiconductors, which affects their fine structure. Brovelliet al. demonstrate a nanoengineering-based approach that provides ...

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 ...

This video excerpt from NOVA's "Hunting the Elements" explains why some elements are more reactive than others.

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 6, 7 and 0 are non-metals.