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

This overview of isotopes explores where isotopes come from and returning an atom to its normal state.

This interactive, scaffolded activity allows students to build an atom within the framework of a newer orbital model. It opens with an explanation of why the Bohr model is incorrect and provides an analogy for understanding orbitals that is simple enough for grades 8-9. As the activity progresses, students build atoms and ions by adding or removing protons, electrons, and neutrons. As changes are made, the model displays the atomic number, net charge, and isotope symbol. Try the "Add an Electron" page to build electrons around a boron nucleus and see how electrons align from lower-to-higher energy. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology. The Concord Consortium develops deeply digital learning innovations for science, mathematics, and engineering. The models are all freely accessible. Users may register for additional free access to capture data and store student work products.

Through three lessons and their four associated activities, students are introduced to concepts related to mixtures and solutions. Students consider how mixtures and solutions and atoms and molecules can influence new technologies developed by engineers. To begin, students explore the fundamentals of atoms and their structures. The building blocks of matter (protons, electrons, neutrons) are covered in detail. The next lesson examines the properties of elements and the periodic table one method of organization for the elements. The concepts of physical and chemical properties are also reviewed. Finally, the last lesson introduces the properties of mixtures and solutions. A comparison of different mixtures and solutions, their properties and their separation qualities are explored.

The Nobel Physics Chairman made this speech when presenting the Prize to Chadwick. It clearly explains the importance and depth of Chadwick's work. Site by Nobel e-Museum.

This lesson plan examines the properties of elements and the periodic table. Students learn the basic definition of an element and the 18 elements that build most of the matter in the universe. The periodic table is described as one method of organization for the elements. The concepts of physical and chemical properties are also reviewed.