The Prefix is Otterbox's least expensive iPhone case. The durable silicone, polycarbonate skeleton build of the OtterBox Prefix is thicker than the Commuter and Reflex, but also the least protective. The Prefix is a one-piece case, meaning that it does not snap in place like the Reflex .
carbon is considered tetravalent because it has four valence electrons the valence electrons are in the outermost shell of the atom and allows carbon to form four bonds to other atoms
Carbon has four electrons in outer shell, and can bond with up to four other atoms (usually H, O, N, or another C). Since carbon can make covalent bonds with another carbon atom, carbon chains and rings that serve as the backbones of organic molecules are possible.Chemical bonds store energy.arbon has four electrons in outer shell, and can bond with up to four other atoms (usually H, O, N, or another C). Since carbon can make covalent bonds with another carbon atom, carbon chains and rings that serve as the backbones of organic molecules are possible. Chemical bonds store energy.