Organic Chemistry Chapter 4 vocabulary

step-by-step description of exactly which bonds break and which bonds form
-The step-by-step pathway from reactants to products, showing which bonds break and which bonds form in what order. The mechanism should include the structures of all intermediates and curved arrows to show the movement of electrons.

each fragment gets one electron;
free radicals are produced

one fragment gets both electrons
ions are produced

radicals are formed
Heat or light must be present.

radicals are consumed and radicals are formed

methyl radical – trigonal planar, 120o, sp2

The study of the energy changes accompanying chemical transformations. is generally concerned with systems at equilibrium.

The study of reaction rates.

A multistep reaction where a reactive intermediate formed in one step brings about a second step that generates the intermediate needed for the following step. (p. 128) initiation step: The preliminary step in a chain reaction, where the reactive intermediate is first formed. propagation steps: The steps in a chain reaction that are repeated over and over to form the product. The sum of the propagation steps should give the net reaction. termination steps: Any steps where a reactive intermediate is consumed without another one being generated.

(displacement) A reaction in which an attacking species (nucleophile, electrophile, or free radical) replaces another group. (p. 228) reaction (Substitution, Nucleophilic, bimolecular): The concerted displacement of one nucleophile by another on an carbon atom. (p. 230) reaction (Substitution, Nucleophilic, unimolecular): A two-step interchange of nucleophiles, with bond breaking preceding bond formation. The first step is ionization to form a carbocation. The second step is the reaction of the carbocation with a nucleophile

A molecule or a fragment of a molecule that is formed in a reaction and exists for a finite length of time before it reacts in the next step. An intermediate corresponds to a relative minimum (a low point) in the reaction-energy diagram. (p. 142) reactive intermediate: A short-lived species that is never present in high concentration because it reacts as quickly as it is formed.

A highly reactive species in which one of the atoms has an odd number of electrons. Most commonly, a radical contains a carbon atom with three bonds and an “odd” (unpaired) electron.

A state of a system such that no more net change is taking place; the rate of the forward reaction equals the rate of the reverse reaction.

A strongly nucleophilic species with a negatively charged carbon atom having only three bonds. The carbon atom has a nonbonding pair of electrons.

A highly reactive species with only two bonds to an uncharged carbon atom with a nonbonding pair of electrons. The simplest carbene is methylene,