1. C Is for Carbon Copyright © Houghton Mifflin Harcourt Publishing Company Why does carbon form many different compounds? Carbon has the ability to form a wide variety of molecules, based on the arrangement of its electrons. A carbon atom has a total of six electrons, two of which are in an inner shell. The four electrons in the outer shell form bonds with other atoms, and are called valence electrons. Unit 4 Lesson 2 Organic Chemistry

2. Why does carbon form many different compounds? Carbon atoms form bonds by sharing their valence electrons with other atoms. Because carbon has four valence electrons, it can form bonds with up to four other atoms at the same time. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 4 Lesson 2 Organic Chemistry

3. How does carbon form molecules? A carbon atom can form up to four single bonds at one time, each bond containing one electron pair. A carbon atom can form a double bond containing two electron pairs. Each carbon atom can form a maximum of two double bonds. A carbon atom can form a triple bond containing three electron pairs. Each carbon atom can form a maximum of one triple bond. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 4 Lesson 2 Organic Chemistry

4. How does carbon form molecules? A carbon atom can form bonds with up to four other carbon atoms, making it possible for long chains of carbon atoms to form. These chains can spread in a straight line, or they can branch off in other directions. The branches may also contain chains, which add to the size of the molecule. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 4 Lesson 2 Organic Chemistry

5. What are the types of structural formulas? The structural formula of a molecule shows how the atoms in the molecule are connected to one another. A full structural formula shows all of the bonds between the atoms of a molecule. In a simplified structural formula, the atoms bonded to each central carbon atom are grouped together. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 4 Lesson 2 Organic Chemistry

6. Copyright © Houghton Mifflin Harcourt Publishing Company An organic compound is a chemical compound that is composed of carbon, hydrogen, and possibly other elements. Many non-living things we use every day are made of organic compounds, such as nylon and heating fuel. Living things are also made up of organic compounds. They provide energy and structure for living things to grow and change. They can also include other elements, such as fluorine, chlorine, oxygen, phosphorus, nitrogen, and sulfur. Unit 4 Lesson 2 Organic Chemistry

7. How are organic compounds classified? A hydrocarbon is an organic compound that contains only carbon atoms and hydrogen atoms. The simplest hydrocarbon is methane, CH 4, which has just one carbon atom bonded to four hydrogen atoms. Some hydrocarbons have more than 20 carbon atoms. Most long-chain hydrocarbons are found in oils and waxes. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 4 Lesson 2 Organic Chemistry

8. How are organic compounds classified? An organic acid is an organic compound that has acidic properties. Organic acids are identified by a group of atoms called a carboxyl group: COOH. In a carboxyl group, one oxygen atom is double- bonded to the carbon atom, and the other oxygen atom is single-bonded to the carbon and hydrogen atoms. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 4 Lesson 2 Organic Chemistry

9. How are organic compounds classified? A carbohydrate is a neutral organic compound containing carbon, hydrogen, and oxygen. There are usually two hydrogen atoms for every oxygen atom. 1:2:1 C:H:O Carbohydrates are one of nature’s energy stores. Carbohydrates can be simple or complex. Simple carbohydrates are small sugar molecules, while complex carbohydrates are long chains of sugar molecules. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 4 Lesson 2 Organic Chemistry

10. What other structures can organic compounds form? Polymers are molecules composed of the same repeating small groups of atoms joined together in long chains. The small units are called monomers. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 4 Lesson 2 Organic Chemistry Technology Can Be Organic Many flat panel screens on electronic devices use organic compounds in a device called an organic light emitting diode (OLED).