This educational brief provides an overview of the concepts of radioactivity, basic particle physics, and the use of radioactive decay as a mechanism to date our galaxy.

The following information will help you understand the Periodic Table of the Isotopes.

Elements: Each element has a fixed number of positively charged protons in its nucleus and an equal number of electrons orbiting the nucleus. For example, hydrogen (H) has one proton and one electron, but lead (Pb) has 82 protons and 82 electrons. There are about 115 known elements of which 82 are naturally abundant.

Isotopes: The nucleus contains both protons and neutrons. An element has a fixed number of protons but may exist with various numbers of neutrons. The sum of the protons and neutrons is the mass number. For example, helium exists as 3He(2 protons and one neutron) or as 4He (2 protons and 2 neutrons). The two forms of helium are called isotopes of helium. Isotopes of an element have the same chemical properties but different weights. Some elements have many isomers. Tin (Sn) has about 38 known isotopes. ~

This survey chemistry course is designed to introduce students to the world of chemistry. In this course, we will study chemistry from the ground up, learning the basics of the atom and its behavior. We will apply this knowledge to understand the chemical properties of matter and the changes and reactions that take place in all types of matter. Upon successful completion of this course, students will be able to: Define the general term 'chemistry.' Distinguish between the physical and chemical properties of matter. Distinguish between mixtures and pure substances. Describe the arrangement of the periodic table. Perform mathematical operations involving significant figures. Convert measurements into scientific notation. Explain the law of conservation of mass, the law of definite composition, and the law of multiple proportions. Summarize the essential points of Dalton's atomic theory. Define the term 'atom.' Describe electron configurations. Draw Lewis structures for molecules. Name ionic and covalent compounds using the rules for nomenclature of inorganic compounds. Explain the relationship between enthalpy change and a reaction's tendency to occur. (Chemistry 101; See also: Biology 105. Mechanical Engineering 004)

This tutorial will help students learn and understand the concepts of geologic time and the age of the Earth. They will investigate the geologic time scale and learn about the use of index fossils and radiometric dating to determine the age of rock formations and fossils.

This film briefly considers the nature of atoms as an introduction to an educational unit on the health effects of ionizing radiation (radioactivity). Educational concepts include atoms, nucleus, proton, neutron, electron, element, isotope, electrical charges, and ions. This instructional film is from Kansas State University's web-based course, GENAG 711, Occupational and Agricultural Health. Copyright 2011, Mitch Ricketts.

This film examines the process of radioactive decay as part of an educational unit on the health effects of ionizing radiation (radioactivity). Educational concepts include radioisotope, radioactive decay, alpha radiation, beta radiation, gamma radiation, x-radiation, decay chain, and half-life. This instructional film is from Kansas State University's web-based course, GENAG 711, Occupational and Agricultural Health. Copyright 2011, Mitch Ricketts.

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.

This unit covers introductory concepts of mixtures and solutions. Students think about how mixtures and solutions, and atoms and molecules can influence new technologies developed by engineers. The first lesson explores the fundamentals of atoms and their structure. 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 discussed.

This site provides access to a number of visual resources and supporting material illustrating the concept of radioactive decay and its central role in radiometric dating. Visualizations include diagrams, graphs, static illustrations and photos. Resources found on this site are suitable for use in lectures and classes and may also be used as the basis for labs or other activities.

If you are curious about the principle underlying stable isotopes studies of hydrogen, carbon, nitrogen, oxygen or sulfur, these pages may be of interest to you. They represent notes used to prepare lectures in stable isotope geochemistry taught at Penn State for a number of years.