Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Define matter and elements
Describe the interrelationship between protons, neutrons, and electrons
Compare the ways in which electrons can be donated or shared between atoms
Explain the ways in which naturally occurring elements combine to create molecules, cells, tissues, organ systems, and organisms

In this video, Paul Andersen explains why atoms in the periodic table show trends in ionization energy, atomic radii, electronegativity and charge. All of these trends are explained through Coulomb's Law. A brief description of Dmitri Mendeleev and the power of predictability are included. [8:47]

The General Chemistry Virtual Textbook, or Chem 1, is broken into several sections covering various aspects of topics related to chemistry. This section deals with chemical bonding and specifically the study of both polar and nonpolar bonds.

Chemical bonds are the glue that hold molecules together. We will learn about the different kinds of bonds, ways chemists draw bonds and molecules, and how the type of chemical bonding affects the bulk properties of a material. We will cover electronegativity, Lewis dot structures, VSEPR, bond hybridization, and ionic, covalent, and metallic bonds.

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

After students conduct the two associated activities, Density Column Lab - Parts 1 and 2, present this lesson to provide them with an understanding of why the density column's oil, water and syrup layers do not mix and how the concepts of density and miscibility relate to water chemistry and remediation. Topics covered include miscibility, immiscibility, hydrogen bonds, hydrophobic and hydrophilic. Through the density column lab activities, students see liquids and solids of different densities interact without an understanding of why the resulting layers do not mix. This lesson gives students insight on some of the most fundamental chemical properties of water and how it interacts with different molecules.

Use this lesson to help understand how to calculate the difference in electronegativity to determine whether a bond is ionic, polar covalent, or nonpolar covalent. [6:55]

Electronegativity is defined and compared to electron affinity. Trends based on groups and periods are also explored. [9:54]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

The Pauling Scale is used to understand bonding due to electronegativity. Bond types are classified. [11:39]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

The interactions of electrons with matter have great explanatory power and are central to many technologies from transistors, diodes, smoke detectors, and dosemeters to sophisticated imaging, lasers, and quantum computing. A conceptual grasp of the interactions of electrons in general allows students to acquire deeper understanding that can be applied to a very broad range of technologies.

After reviewing different types of bonding, students predict the type of bond that will form between two different atoms using periodic trends and electronegativity data. [4:04]

Students are challenged to use computer-aided design (CAD) software to create “complete” 3D-printed molecule models that take into consideration bond angles and lone-pair positioning. To begin, they explore two interactive digital simulations: “build a molecule” and “molecule shapes.” This aids them in comparing and contrasting existing molecular modeling approaches—ball-and-stick, space-filling, and valence shell electron pair repulsion (VSEPR)—so as to understand their benefits and limitations. In order to complete a worksheet that requires them to draw Lewis dot structures, they determine the characteristics and geometries (valence electrons, polar bonds, shape type, bond angles and overall polarity) of 12 molecules. They also use molecular model kits. These explorations and exercises prepare them to design and 3D print their own models to most accurately depict molecules. Pre/Post quizzes, a step-by-step Blender 3D software tutorial handout and a worksheet are provided.

The periodic table of elements is one of the greaest achievement in chemistry, and understanding its arrangment helps us to understand many aspects of chemistry. This pathway provides resources to understand several of the trends on the periodic table, such as electronegativity and the number of bonds an atom can form.

An interactive simulation that teaches about polarity, electronegativity, and bonds by changing the electronegativity of atoms and bond angles in a molecule to see how it affects polarity. This simulation can either be downloaded or played online and includes handouts, lesson plans, and additional materials.

Learn how to classify bonds as covalent, polar covalent or ionic by using the differences in electronegativity in this video. Video explains the Pauling scale to find the electronegativity differences in bonding. [11:38]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.