Nuggets of Knowledge for Chapter 1 – Atoms and Molecules Chem 2310I. Introduction to Organic Chemistry● Organic chemistry began in the 1700's as the study of compounds which came from living things, like sugars, urea, and quinine. ○ These compounds were found to be much more complicated than chemicals like sodium chloride or magnesium sulfate which were obtained from minerals in the earth. ○ For a time, chemists believed that they contained a special “vital energy” and could not be created in the laboratory, unlike inorganic chemicals. ○ Eventually, however, they realized that the big difference was that the organic chemicals all contained a large proportion of the element carbon, while only a few types of minerals contained carbon. Once carbon’s bonding properties were understood, chemists began to make progress in analyzing and synthesizing organic chemicals.● Organic chemistry now involves the study of all chemicals containing carbon, whether or not they originated with living things. Since those early days, organic chemists have amassed a huge body of knowledge about the structure of organic chemicals and how they behave, and have learned to make many organic compounds that are not found in nature. A two semester course can barely scratch the surface of what is now known, and there is still more to be discovered. ● Organic chemistry is typically taken in the sophomore year of college, since it is a stepping stone to more advanced chemistry courses, such as biochemistry, and is also important for the study of botany, zoology, and medical fields such as nutrition, physiology, pharmacy, medicine, and dentistry.● Many industries also depend on organic chemistry. ○ Pharmaceutical companies create and manufacture drugs, which are nearly all organic chemicals, since they are intended to interact with the organic chemicals the body is made of. ○ Petroleum, which is thought to have come from the remains of tiny microscopic animals in the ancient oceans, is a complex organic mixture found under the earth which can be separated and modified to make many of the products we use for fuel, including gasoline, diesel, kerosene, and heating oil. ○ Plastics, which can be made in an astounding variety of properties, are also made from petroleum. ○ Pesticides and fertilizers are also made from organic compounds.● It is unusual that an entire branch of chemistry would be based on just one element. There are several reasons for this.○ One reason is that there is such a staggering number of different organic chemicals. 95% of all of the known compounds are organic – and that total is over 15 million different compounds. ■ The reason there are so many organic compounds is that the element carbon has a unique ability to form complex structures. No other element will form stable chains, rings, and other combinations like carbon does. ■ Organic compounds are made up with a framework of these carbon structures with hydrogen, oxygen, nitrogen, and other elements attached in a variety of stable patterns. ● The other reason is that this makes possible the very complex molecules that are required for life, such as DNA, proteins, carbohydrates, lipids, and so on. Because of this, understanding how organic chemicals behave is necessary to studying how living things work.II. Review of Atomic Structure Elementary particles ● All atoms are made of three elementary particles – protons, neutrons, and electrons. ● Protons, which have a positive charge, and neutrons, which have no charge, are found in the nucleus of the atom. ● Electrons, which have a negative charge, are found outside the nucleus, and are the part of the atom which participates in chemical reactions. The Periodic Table of Elements ● There are 90 kinds of atoms that can be found in nature (more can be made using nuclear reactions). These are called the elements. They are the fundamental substances that make up all of the matter in the universe.● The different elements are distinguished by the number of protons in their nucleus, which is called the atomic number. The number of protons is what gives the atom its identity.○ For example, the smallest element is hydrogen, with an atomic number of one. This means that all hydrogen atoms have one proton in their nucleus, and that any atom with only one proton must be a hydrogen atom, no matter how many neutrons or electrons it has. ● The elements are organized into the Periodic Table of Elements. It starts with hydrogen, which has an atomic number of 1, and then goes across to helium, atomic number 2, then starts a new row with lithium, atomic number 3, and so on.● This arrangement of the elements is very powerful because it allows us to deduce many things about an element based on its position of the table.○ The elements which are metallic in their elemental state are located to the left of the stair-step line, while elements which are gases or crystals in their elemental state (except hydrogen) are located to the right of the stair-step line. ■ Metals are further divided into main group metals, transition metals, and inner transition metals. Main group metals are found in the first two columns and under the stair step line; transition metals are located in the middle of the metals, and inner transition metals are in the two lines below the table (which actually fit before the transition metals). ○ A row on the Periodic Table is called a period. ■ Periods are numbered from the top – hydrogen and helium make up the first period, lithium through neon the second, and so on. ■ The elements in a period are about the same size.○ A column on the Periodic Table is called a family or group. ■ Elements in the same family tend to have similar chemical reactivity. However, they get larger as you go down, which changes their behavior some. ■ Some of the families have names, such as the alkali metals (the first group), the alkaline earth metals (the second group), the halogens (the second to last group), and the noble gases (the last group). ● Organic chemistry only uses a few of the elements on the Periodic Table. ○ Most organic chemicals are made of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). ○ Halogens, the second to last family on the Periodic Table, are also found in many organic chemicals. They are fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). ○ Occasionally