UNIT 7 Nomenclature What is the System Used to Name Chemical Compounds? Thinking clearly and effectively is the greatest asset of any human being. Harry Lorayne (1926– ) Engage: Are Scientists Memory Experts? Are You? A. What do pyrite, iron sulfide, and ferrous sulfide have in common? Explain the similarities and differences among grain alcohol, ethanol, and ethyl alcohol. What are the elemental symbols for silver and gold? Before Studying this Unit After Studying this Unit B. Why is CaO named calcium oxide whereas CO is named carbon monoxide? A pyrite crystal. Before Studying this Unit After Studying this Unit 1. Harry Lorayne gained a great deal of notoriety in the 1970s as the world’s foremost memory expert. More than two million copies of his book, The Memory Book, with co- author Jerry Lucas, were sold. A reprint of the book continues to be in print. Mr. Lorayne used his phenomenonal memory to become a best-selling author, magician, entertainer, and lecturer. He is not a scientist. Most scientists have average memories. Few scientists have ever read Mr. Lorayne’s book or done any specialized work in improving their memories. Yet the typical chemist knows how to name thousands of chemical compounds. How do chemists know so Harry Lorayne (1926 – ), memory many chemical names? This knowledge is accomplished by learning a system for naming expert. rather than memorization of individual names. Unit 7 Page 1 Copyright © 2012 Montana Partners This project was largely funded by an ESEA, Title II Part B Mathematics and Science Partnership grant through the Montana Office of Public Instruction. High School Chemistry: An Inquiry Approach 2. Let’s test your short-term memory. You’ll need to work with a partner on this task. Below is a list of the first five hundred digits in pi, the ratio of the circumference to the diameter of a circle. 3.14159265358979323846264338327950288419716939937510582097494459230781640 628620899862803482534211706798214808651328230664709384460955058223172535 940812848111745028410270193852110555964462294895493038196442881097566593 344612847564823378678316527120190914564856692346034861045432664821339360 Pi (π) is the ratio of the circumference 726024914127372458700660631558817488152092096282925409171536436789259036 to the diameter of a circle. The distance around a circle is its 001133053054882046652138414695194151160943305727036575959195309218611738 circumference. The distance across 1932611793105118548074462379962749567351885752724891227938183011949 the circle is its diameter. Choose segments of numbers at random. Read different sequences of numbers to your partner at a steady rate of about one per second. Start with three and work up to four, five, etc., as your partner is able to successfully repeat the sequence backwards to you. Continue until your partner reaches his or her maximum ability. The maximum number of digits that can be repeated backwards is an approximate measure of your short-term memory capacity. Most people can remember between six and eight digits. How many digits can you remember long enough to repeat backwards? Explore 1: What Symbols are Used to Represent Elements? 3. Jöns Jakob Berzelius was a Swedish physician, scientist, and teacher. In 1807, Berzelius became a chemistry teacher at Sweden’s medical school. He was distressed by having to require his students to memorize a series of astrologically-based symbols that were then used as shorthand for the names of the elements. For example, the symbol for silver was and gold was . Furthermore, John Dalton proposed a new set of symbols that assigned to hydrogen. It was a confusing time to be a student of chemistry! Berzelius decided to introduce a new, simpler system for symbols to represent the elements. To avoid any controversies that could arise from working with any living language, such as English, French, or Spanish, he worked with elemental names in Latin. His system assigned the first letter of the Latin name of the element as the elemental symbol. Where there was more than one element with the same first letter, a second letter was used. Thus, hydrogen was symbolized with H, and Helium had the Jöns Jacob Berzelius (1779– 1848) was a Swedish chemistry symbol He. teacher who first invented a system of letters to represent So do you need to know the Latin names of the elements to know elemental symbols? chemical elements. Yes and no. Fortunately for English speakers, the first letter or two of most elemental names in Latin are the same as in the English word. A few exceptions exist, however, and it helps in learning the symbols if you have some familiarity with the Latin names of those elements. Unit 7 Page 2 Copyright © 2012 Montana Partners This project was largely funded by an ESEA, Title II Part B Mathematics and Science Partnership grant through the Montana Office of Public Instruction. Unit 7 Nomenclature Latin Name Symbol English Name Natrium Na Sodium Kalium K Potassium Ferrum Fe Iron Argentum Ag Silver Stannum Sn Tin Hydragyrum Hg Mercury Plumbum Pb Lead Explain 1 Sodium is a soft, silvery-white solid at room temperature. It is typically 4. Your beginning step in learning the language of chemistry is to learn the equivalent of stored in kerosene or mineral oil to the alphabet. You need to memorize 35 name–symbol pairs for the common elements. keep it from reacting with the You probably already know some symbols, so your personal learning process will oxygen and moisture in the air. Its require you to only work on the symbols of a subset of our list of 35 elements. Cover chemical symbol, Na, is derived from its Latin name natrium. the element columns in the table below and see how many elements you can name. Z Symbol Element Z Symbol Element 1 H Hydrogen 19 K Potassium 2 He Helium 20 Ca Calcium 3 Li Lithium 24 Cr Chromium 4 Be Beryllium 25 Mn Manganese 5 B Boron 26 Fe Iron 6 C Carbon 27 Co Cobalt 7 N Nitrogen 28 Ni Nickel 8 O Oxygen 29 Cu Copper 9 F Fluorine 30 Zn Zinc 10 Ne Neon 35 Br Bromine 11 Na Sodium 36 Kr Krypton 12 Mg Magnesium 47 Ag Silver 13 Al Aluminum 50 Sn Tin 14 Si Silicon 53 I Iodine 15 P Phosphorus 56 Ba Barium 16 S Sulfur 80 Hg Mercury 17 Cl Chlorine 82 Pb Lead 18 Ar Argon Learning the symbols of the elements works best if you associate the symbol with its position in the periodic table as you learn it. We’ve provided a partial periodic table below. It has only the atomic number and symbol of the 35 symbols that need to be committed to memory. Work through our list a few times while looking at nothing but a periodic table. Once you’ve successfully made it through the list on your own, work with a partner, alternating names and symbols in random order, quizzing one another until you are confident you’ve memorized the name–symbol pairs. Then take the quiz that follows. Unit 7 Page 3 Copyright © 2012 Montana Partners This project was largely funded by an ESEA, Title II Part B Mathematics and Science Partnership grant through the Montana Office of Public Instruction. High School Chemistry: An Inquiry Approach From Cracolice, M. S., & Peters, E. I. (2011). Introductory Chemistry: An Active Learning Approach. Belmont: CA: Brooks/Cole Cengage Learning. 5. Elemental Symbol Quiz Instructions: For each name, write the symbol. For each symbol, write the name. Spelling must be correct for credit! a) mercury b) P c) iron d) F e) sodium f) Ag g) tin h) K i) barium j) Zn k) nitrogen l) Cr Unit 7 Page 4 Copyright © 2012 Montana Partners This project was largely funded by an ESEA, Title II Part B Mathematics and Science Partnership grant through the Montana Office of Public Instruction. Unit 7 Nomenclature Elaborate 1: What are the Formulas of the Elements? 6. The smallest particle in a sample of most elements is a single atom. The symbol used to represent this particle is the symbol of the element. When we write Fe, for example, that symbol represents an atom of iron. For some elements, the smallest particle in a sample is a diatomic molecule, a particle that consists of two (di–) atoms chemically bonded to one another. When we write a symbol to represent this particle, it needs to express the diatomic nature of the molecular particle. Thus, the chemical formula of a diatomic molecule is written as H2, for example, where the subscript 2 indicates that two atoms of hydrogen are joined to form a single hydrogen molecule. 7. When 0.045 gram of hydrogen is placed in a balloon at 21°C and 771 mm Hg, the A diatomic molecule is made volume of the gas is 533 mL. Explain how these data indicate that hydrogen gas exists up of two atoms chemically as diatomic molecules. bonded to one another to form a single molecular particle. 8. A total of seven elements exist as diatomic molecules at common temperature and pressure conditions. Each of these elements, therefore, has the formula X2, where X is the symbol of the element. The seven elements are: hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. They are summarized in the illustration below to help you form a connection between the elements and their position in the periodic table. From Cracolice, M. S., & Peters, E. I. (2011). Introductory Chemistry: An Active Learning Approach. Belmont: CA: Brooks/Cole Cengage Learning. Unit 7 Page 5 Copyright © 2012 Montana Partners This project was largely funded by an ESEA, Title II Part B Mathematics and Science Partnership grant through the Montana Office of Public Instruction. High School Chemistry: An Inquiry Approach 9. Some elements exist as polyatomic molecules. The prefix poly- means many, and thus polyatomic molecules have many atoms, usually implying more than two. For example, sulfur most commonly exists as a molecule with eight atoms in a ring, S8.