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
The shared valence electrons between two nonmetal atoms is called a covalent bond. Covalent bonds are formed when two atoms begin sharing electrons. The electrons are attracted to the positively charged nuclei of the atoms. A dipole results when electrons in a covalent bond are not shared evenly between the two atoms.he shared valence electrons between two nonmetal atoms is called a covalent bond. Think about the term covalent. 'Co' means share and 'valent' refers to valence electrons. Two shared electrons are known as a single covalent bond.