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
it is tetrahedral because in cf4 there are 4 pairs of valence electron and they all are bond pairs there are not any lone pair so it is 100% tetrahedral. â¦  Each florine is more electrongative than the carbon and tend to  attract electrons more than the carbom giving the florines a  negative charge. In most situations this would lead to the molecule  being polar but remember! The florines are opposite of eachother.