When the outermost orbit of an atom has exactly 4 valence electrons, the material is most likely a semiconductor. Semiconductors are materials that have an intermediate level of electrical conductivity between conductors and insulators. The presence of four valence electrons in the outermost orbit suggests that the material belongs to Group 14 of the periodic table, also known as the carbon group. Elements in this group, such as carbon (C), silicon (Si), and germanium (Ge), typically exhibit semiconductor properties. These materials can be used in a wide range of electronic devices, including transistors, diodes, and integrated circuits.