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 (from Latin: carbo coal) is a chemical element with symbol C and atomic number 6. On the Periodic table, it is the first (row 2) of six elements in column (group) 14, which have in common the composition of their outer electron shell.It is nonmetallic and tetravalent âmaking four electrons available to form covalent chemical bonds.n the Periodic table, it is the first (row 2) of six elements in column (group) 14, which have in common the composition of their outer electron shell. It is nonmetallic and tetravalent âmaking four electrons available to form covalent chemical bonds.