Unit 3 B.1-B.4

A polymer is a molecule composed of very large numbers of identical repeating units and a monomer is a compound where the molecules react to form the repeating units of a polymer. In chemistry there is a branch called organic chemistry that deals with hydrocarbons. In hydrocarbon molecules, carbon atoms that are chemically linked to one another is called a carbon chain. In an atom the shell surrounds the atom's nucleus with one or more electrons. The first shell surrounding the nucleus has a capacity of two electrons and the second shell has the capacity to hold eight electrons. Every atom combines with another atom to get eight electrons in its shell. The electrons in the outer most shell are called valence electrons. A covalent bond is the sharing of two or more valence electrons between two atoms. The Lewis dot structures helps indicate covalent bonds. Another way to represent a covalent bond would be by drawing a line and this is called a structural formula. Petrochemicals are any organic compounds that are produced from petroleum or natural gas. An addition reaction is a reaction at the double or triple bond within an organic molecule and an addition polymer is a polymer that is formed by repeated addition reactions.