CHEM1: Organic Chemistry CHAPTER 1: INTRODUCTION AND REVIEW Organic Chemistry started as the chemistry of life, then that was thought to be different from the chemistry in the laboratory. Then it became the chemistry of carbon compounds, especially those found in coal. But now it is both. It is the chemistry of the compounds formed by carbon and other elements such as are found in living things, in the products of living things, and wherever else carbon is found. TAKE NOTE: ORGANIC CHEMISTRY is carbon centric. Carbon is the key atom on all these molecules and carbon atoms do some very predictable things, like make or form bonds. Urea- is the main nitrogen containing part if urine that comes from our body’s metabolic breakdowns of proteins. But it’s also a great fabric dye mordant which is a chemical that makes the dye last longer often enhances the color. In the 19th century, experiments showed that organic compounds could be synthesized from inorganic compounds. 1828- the German chemist Friedrich Wohler converted ammonium cyanate, made from ammonia and cyanic acid, to urea simply by heating it in the absence of oxygen. Today, organic chemistry is defined as the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds. This definition includes chemicals extracted from living things, but also man-made polymers, like plastics. A BRIEF HISTORY The term organic literally means “derived from living organisms”.” Originally, the science of organic chemistry was the study of compounds extracted from living organisms and their natural products. Compounds such as sugar, urea, starch, waxes, and plant oil were considered “organic”, and people accepted Vitalism, the belief that natural products needed a “vital force” to create them. Chemists have learned to synthesize pr simulate many of these complex molecules. The synthesized products serve as drugs, medicines, plastics, pesticides, paints, and fibers. Many of the most important advances in medicine are actually advances in organic chemistry. New synthetic drugs are developed to combat disease, and new polymers are molded to replace failing organs. Organic chemistry has gone full circle. It began as the study of compounds derived from “organs”, and now it gives us the drugs and materials we need to save or replace those organs. PRNCIPLES OF ATOMIC STRUCTURE nucleus, but it is the electrons that take part in chemical bonding and reactions. Types of Chemical Bonds Chemical bonding describes a variety of interactions that hold atoms together in chemical compounds. Key Points ATOMS- are made up of protons, neutrons, and electrons. Atoms are the fundamental building blocks of chemistry. Matter itself is made of a collection of different types of atoms. Scientists discovered 118 kinds of atoms which we call ELEMENTS. Key Terms PROTONS- are positively charged and are found together with (uncharged) neutrons in the nucleus. ELECTRONS- which have a negative charge that is equal in magnitude to the positive charge on the proton, occupy the spaced surrounding the nucleus. Protons and Neutrons- have similar masses, about 1800 times the mass of an electron. Almost all the atom’s mass is in the Chemical bonds are forces that hold atoms together to make compounds or molecules. Chemical bonds include covalent, polar covalent, and ionic bonds. Atoms with relatively similar electronegativities share electrons between them and are connected by covalent bonds. Atoms with large differences in electronegativity transfer electrons to form ions. The ions then are attracted to each other. This attraction is known as an ionic bond. bond: A link or force between neighboring atoms in a molecule or compound. ionic bond: An attraction between two ions used to create an ionic compound. This attraction usually forms between a metal and a non-metal. covalent bond: An interaction between two atoms, which involves the sharing of one or more electrons to help each atom satisfy the octet rule. This interaction typically forms between two non-metals. intramolecular: Refers to interactions within a molecule. intermolecular forces: Refers to interactions between two or more molecules. Chemical bonds Chemical bonds are the connections between atoms in a molecule. These bonds include both strong intramolecular interactions, such as covalent and ionic bonds. They are related to weaker intermolecular forces, such as dipole-dipole interactions, the London dispersion forces, and hydrogen bonding. The weaker forces will be discussed in a later concept. Chemical bonds: This picture shows examples of chemical bonding using Lewis dot notation. Hydrogen and carbon are not bonded, while in water there is a single bond between each hydrogen and oxygen. Bonds, especially covalent bonds, are often represented as lines between bonded atoms. Acetylene has a triple bond, a special type of covalent bond that will be discussed later. 1. Ionic Bonding - A transfer of one electron gives each of two elements a noble-gas configuration. The resulting ions have opposite charges, and they attract each other to form an ionic bond. LEWIS STRUCTURE - is a very simplified representation of the valence shell electrons - 2. Covalent bonding In which electrons are shared rather than transferred, is the most common type of bonding in organic compounds. in a molecule. It is used to show how the electrons are arranged around individual atoms in a molecule. Electrons are shown as "dots" or for bonding electrons as a line between the two atoms. The goal is to obtain the "best" electron configuration, i.e. the octet rule and formal charges need to be satisfied.