Professor’s eyes only… You may be surprised to learn… …that over 25% of all undergraduate students do not utilize their required course material. …student retention is dropping nationwide and while the higher education community has done a remarkable job of opening the doors of college to more and more students, we have not seen equal strides in the number of students who actually complete four-year degrees. (Education Trust, 2004) See the next slide on what you can do… Chapter two slides begin on slide 17 Professor: Course/Section:

Professor’s eyes only… What you can do… The top factors motivating a student to use their adopted books all involve whether the material is immediately used, referred to, or assessed from in the classroom. Please take a few minutes the first day of class to explain and demonstrate why you adopted your book and accompanying technology. The next few slides show the book, technology products, and messaging to students that indicates they will be responsible for the content. Feel free to customize the information or delete from your slide set. Professor: Course/Section:

Bettelheim/Brown/Campbell/Farrell Introduction to General, Organic, & Biochemistry, 8e Professor: Course/Section: This is your required course material You will need this material for: - tests and quizzes - homework and reading assignments

Some of the reasons why you need to use the new edition… Professor: Course/Section: The book's increased emphasis on key skills includes new "How To" features, such as "How to Balance a Nuclear Equation," "How to Draw Lewis Structures," and "How To Draw Curved Arrows and Push Electrons." Updated biochemistry content (by authors, Mary Campbell and Shawn Farrell) provides the latest information on this fast-growing field. Nuclear Chemistry is now covered in Chapter 3 so allied health students get to the study of Nuclear Medicine more quickly.

More reasons why you need to use the new edition… Professor: Course/Section: New "Tying It Together," "Looking Ahead," and "Challenging Problems" at the end of most chapters gives you a more challenging way to gauge your knowledge. New Chemical Connections boxes include ethylene as a plant growth regulator, the development of new asthma medications, and the action of anti-inflammatory drugs.

If you purchased a used book, order ThomsonNOW with ISBN # X ThomsonNow for General, Organic, and Biochemistry is a powerful online learning tool that helps you assess your unique study needs, and available with each new copy of Bettelheim et. al’s Introduction to General, Organic, and Biochemistry, 8e. Videos Learning Modules Case Studies Primary Source Materials Full e-Book Animations/Interactivities Exams Weblinks study less, learn more!

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The 48 experiments in this well-conceived manual illustrate important concepts and principles in general, organic and biochemistry. All experiments include Pre and Post-Lab Questions, which have been revised for the new edition. Lab Experiments Buy ISBN #

Buy ISBN # Student Solutions Manual The best way for you to learn and understand the concepts is to work multiple, relevant problems on a daily basis. This is a comprehensive guide to working the solutions to the odd-numbered end-of-chapter problems in the text. The Student Solutions Manual provides you instant feedback by not only giving the answers but also giving detailed explanations.

Students Please Read… If your textbook doesn’t already come with the helpful study aids we’ve discussed, go to your local college bookstore or go on-line to the textbook URL … Professor: Course/Section:

© 2006 Thomson Learning, Inc. All rights reserved General, Organic, and Biochemistry, 8e Bettelheim, Brown Campbell, & Farrell

© 2006 Thomson Learning, Inc. All rights reserved Chapter 2 Atoms Atoms

© 2006 Thomson Learning, Inc. All rights reserved Classification of Matter

© 2006 Thomson Learning, Inc. All rights reserved Classification of Matter Element: Element: a substance (for example, carbon, hydrogen, and iron) that consists of identical atoms. There are 116 known elements. Of these, 88 occur in nature; the others have been made by chemists and physicists. Their symbols consist of one or two letters. Names are derived from a variety of sources: the English name of the element, people important in atomic science, geographic locations, planets, mythological sources, etc.

© 2006 Thomson Learning, Inc. All rights reserved Classification of Matter Compound: Compound: a pure substance made up of two or more elements in a fixed ratio by mass. Formula of a compound: Formula of a compound: tells us the ratios of its constituent elements and identifies each element by its atomic symbol. NaCl: the ratio of sodium atoms to chlorine atoms in sodium chloride is 1:1 H 2 O: the ratio of hydrogen atoms to oxygen atoms in water is 2:1

© 2006 Thomson Learning, Inc. All rights reserved A Water Molecule

© 2006 Thomson Learning, Inc. All rights reserved Classification of Matter Mixture: Mixture: a combination of two or more pure substances The substances may be present in any mass ratio. Each substance has a different set of physical properties. Mixtures may be homogeneous or heterogeneous. If we know the physical properties of the individual components of the mixture, we can use appropriate physical means to separate the mixture into its component parts.

© 2006 Thomson Learning, Inc. All rights reserved Dalton’s Atomic Theory atoms All matter is composed of very tiny particles, which Dalton called atoms. All atoms of the same element have the same chemical properties. Atoms of different elements have different chemical properties. Compounds Compounds are formed by the chemical combination of two or more of the same or different kinds of atoms. molecule A molecule is a tightly bound combination of two or more atoms that acts as a single unit.

© 2006 Thomson Learning, Inc. All rights reserved Evidence for Dalton’s Theory Law of Conservation of Mass Matter can be neither created or destroyed. As Dalton explained, if matter is made up of indestructible atoms, then any chemical reaction just changes the attachments among atoms, but does not destroy the atoms themselves.

© 2006 Thomson Learning, Inc. All rights reserved Evidence for Dalton’s Theory Law of Conservation of Mass Law of Conservation of Mass Monatomic elements: Monatomic elements: consist of single atoms; for example, helium (He) and neon (Ne). Diatomic elements: Diatomic elements: there are seven elements that occur as diatomic molecules: H 2, N 2, O 2, F 2, Cl 2, Br 2, and I 2 Polyatomic elements: Polyatomic elements: some elements have three or more atoms per molecule: O 3, P 4, S 8 diamond has millions of carbon atoms bonded together to form one gigantic cluster.

© 2006 Thomson Learning, Inc. All rights reserved Subatomic Particles Table 2.1 Properties and Location within Atoms of Protons, Neutrons and Electrons atomic mass unit (amu) The unit of mass is the atomic mass unit (amu) By definition, 1 amu 1/12 the mass of a carbon atom with 6 protons and 6 neutrons. 1 amu = x g

© 2006 Thomson Learning, Inc. All rights reserved A Typical Atom Protons and neutrons are found in the nucleus, and electrons are found as a cloud outside the nucleus.

© 2006 Thomson Learning, Inc. All rights reserved Mass and Atomic Numbers Mass number: Mass number: the number of protons and neutrons in the nucleus of an atom. the mass of the electrons in an atom is so small compared to that of its protons and neutrons that electrons are not counted in determining mass number. Atomic number: Atomic number: the number of protons in the nucleus of an atom. a carbon atom of this composition is referred to as carbon-12.

© 2006 Thomson Learning, Inc. All rights reserved Isotopes Isotopes: Isotopes: atoms with the same number of protons but a different number of neutrons. carbon-12 has 6 protons and 6 neutrons; carbon-13 has 6 protons and 7 neutrons; carbon-14 has 6 protons and 8 neutrons; Most elements found on Earth are mixtures of isotopes: chlorine is 75.77% chlorine-35 (18 neutrons) and 24.23% chlorine-37 (20 neutrons).

© 2006 Thomson Learning, Inc. All rights reserved Atomic Weight Atomic weight: Atomic weight: the weighted average of the masses (in amu) of the naturally occurring isotopes of an element. example: chlorine is 75.77% chlorine-35 and 24.23% chlorine-37

© 2006 Thomson Learning, Inc. All rights reserved Mass and Size of an Atom Consider an atom of lead-208: it has 82 protons, 82 electrons, and 126 neutrons it has a mass of 3.5 x g It requires 1.3 x atoms to make 1 lb of lead-208. The diameter of the nucleus is about 1.6 x m. The diameter of the atom is 3.5 x m. The density of the atom is 11.3 g/cm 3. The density of the nucleus is 1.8 x g/cm 3.

© 2006 Thomson Learning, Inc. All rights reserved Periodic Table Dmitri Mendeleev ( ) arranged the known elements in order of increasing atomic weight beginning with hydrogen. He observed that when elements are arranged in this manner, certain sets of properties recur periodically. column periodsHe then arranged elements with recurring sets of properties in the same column (vertical row); Li, Na, and K, for example, fall in the same column and start new periods (horizontal rows).

© 2006 Thomson Learning, Inc. All rights reserved Periodic Table Fluorine, chlorine, bromine, and iodine fall in the same column

© 2006 Thomson Learning, Inc. All rights reserved Classification of elements Figure 2.9 Classification of the elements.

© 2006 Thomson Learning, Inc. All rights reserved Classification of Elements Metals Metals are solids at room temperature (except for Hg, which is a liquid), shiny, conduct electricity, and are ductile and malleable. form alloys (solutions of one metal dissolved in another); brass, for example, is an alloy of copper and zinc. In chemical reactions, they tend to give up electrons. Nonmetals Nonmetals Except for hydrogen (H), they lie on the right side of the Periodic Table. Except for graphite, do not conduct electricity. In chemical reactions, they tend to accept electrons.

© 2006 Thomson Learning, Inc. All rights reserved Classification of Elements Metalloids Metalloids They have some of the properties of metals and some of nonmetals; for example, they are shiny like metals but do not conduct electricity. Six elements are classified as metalloids: boron, silicon, germanium, arsenic, antimony, and tellurium. One of the metalloids, silicon, is a semiconductor; it does not conduct electricity under certain applied voltages, but becomes a conductor at higher applied voltages.

© 2006 Thomson Learning, Inc. All rights reserved Examples of Periodicity Table 2.2 The halogens (Group 7A elements)

© 2006 Thomson Learning, Inc. All rights reserved Examples of Periodicity Table 2.3 The alkali metals (Group 1A elements)

© 2006 Thomson Learning, Inc. All rights reserved Examples of Periodicity The noble gases, Group 8A elements

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Electron configuration: Electron configuration: the arrangement of electrons in the extranuclear space quantized The energy of electrons in an atom is quantized, which means that an electron in an atom can have only certain allowed energies. Ground-State electron configuration: Ground-State electron configuration: the electron configuration of the lowest energy state of an atom

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Table 2.5 Distribution of Electrons in Shells

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Table 2.6 Distribution of Orbitals within Shells

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Orbitals have definite shapes and orientations in space

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Electron configurations are governed by three rules: Rule 1: Rule 1: orbitals fill in the order of increasing energy from lowest to highest: elements in the first, second, and third periods fill in the order 1s, 2s, 2p, 3s, and 3p.

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Figure 2.13 Energy levels for orbitals through the third shell.

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Rule 2: Rule 2: each orbital can hold up to two electrons with spins paired. with four electrons, the 1s and 2s orbitals are filled and are written 1s 2 2s 2. with an additional six electrons, the three 2p orbitals are filled and are written either 2p x 2 2p y 2 2p z 2, or they may be written 2p 6.

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Figure 2.14 The pairing of electron spins.

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Rule 3: Rule 3: when there is a set of orbitals of equal energy, each orbital becomes half filled before any of them becomes completely filled. example:example: after the 1s and 2s orbitals are filled, a 5th electron is put into the 2p x, a 6th into the 2p y, and a 7th into the 2p z. Only after each 2p orbital has one electron is a second added to any 2p orbital.

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Orbital box diagrams Orbital box diagrams a box represents an orbital. an arrow represents an electron. a pair of arrows with heads in opposite directions represents a pair of electrons with paired spins. Example Example: carbon (atomic number 6)

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Noble gas notation the symbol of the noble gas immediately preceding the particular atom indicates the electron configuration of all filled shells Example: Example: carbon (atomic number 6)

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Valence shell: Valence shell: the outermost incomplete shell. Valence electron: Valence electron: an electron in the valence shell. Lewis dot structure: the symbol of the element represents the nucleus and filled shells. dots represent valence electrons.

© 2006 Thomson Learning, Inc. All rights reserved

© 2006 Thomson Learning, Inc. All rights reserved Electron Configuration Table 2.9 Noble Gas Notation and Lewis dot structures for the Alkali Metals (Group 1A Elements)

© 2006 Thomson Learning, Inc. All rights reserved Periodic Property As we have seen, the Periodic Table was constructed on the basis of trends (periodicity) in chemical properties. With an understanding of electron configuration, chemists realized that the periodicity of chemical properties could be understood in terms of periodicity in electron configuration. The Periodic Table works because elements in the same column (group) have the same configuration in their outer shells. We look at two periodic properties: atomic size and ionization energy

© 2006 Thomson Learning, Inc. All rights reserved Atomic Size The size of an atom is determined by the size of its outermost occupied orbital. Example: the size of a chlorine atom is determined by the size of its three 3p orbitals, the size of a carbon atom is determined by the size of if its three 2p orbitals.

© 2006 Thomson Learning, Inc. All rights reserved Atomic Size Figure 2.16 Atomic radii of the main-group elements (in pm).

© 2006 Thomson Learning, Inc. All rights reserved Ionization Energy Ionization energy: Ionization energy: the energy required to remove the most loosely held electron from an atom in the gaseous state. example: when lithium loses one electron, it becomes a lithium ion; it still has three protons in its nucleus, but now only two electrons outside the nucleus.

© 2006 Thomson Learning, Inc. All rights reserved Ionization Energy Figure 2.17 Ionization energy versus atomic energy for elements 1-37.

© 2006 Thomson Learning, Inc. All rights reserved Ionization Energy Ionization energy is a periodic property: in general, it increases across a row; valence electrons are in the same shell and subject to increasing attraction as the number of protons in the nucleus increases. it increases going up a column; the valence electrons are in lower principle energy levels, which are closer to the nucleus and feel the nuclear charge more strongly.

© 2006 Thomson Learning, Inc. All rights reserved End Chapter 2 Atoms