Explains the basics of atomic structure, from simple definitions to information about quantum theory. Accurate and helpful basics whether or not you need the more advanced information.
This pathway introduces the building block of all matter, the atom, and some of the key experiments that helped scientists discover the subatomic particles that give atoms their unique properties.
The difference between atomic weight and atomic mass in chemistry, and how it compares to the physics definitions of weight and mass.
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Examine the composition of matter.
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Site provides the ABC's of nuclear science including radioactivity and gamma decay to fission and comic rays.
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
A video investigating the makeup of an atom. Learn that atoms are composed of protons, neutrons, and electrons. Understand that protons and neutrons determine the mass of an atom. Also, the atomic number gives you the number of protons in the nucleus. [21:05]
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.
In this interactive activity, learners build computer models of atoms by adding or removing electrons, protons, and neutrons. It presents the orbital model of an atom: a nucleus consisting of protons and neutrons with electrons surrounding it in regions of high probability called orbitals. Guided tasks are provided, such as constructing a lithium atom and a carbon-12 atom in the fewest possible steps. The activity concludes with a model for building a charged hydrogen atom (an ion). Within each task, students take snapshots of their work product and answer probative questions. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology.
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.
Are all atoms of an element the same? How can you tell one isotope from another? Use the sim to learn about isotopes and how abundance relates to the average atomic mass of an element.
Are all atoms of an element the same? How can you tell one isotope from another? Use the sim to learn about isotopes and how abundance relates to the average atomic mass of an element.
