Students use X-ray data to identify an object as a rotating neutron star, and determine its period of rotation. They use XTE observations of the Crab Pulsar to determine the period of the light intensity, interpret this period as the...

In this elements instructional activity, students review the periodic table and how the elements are organized in the periodic table. This instructional activity has 5 short answer and 4 fill in the blank questions.

Fourth graders identify eleven white substances that are commonly found in the household. They, in pairs, perform experiments on a variety of substances, and must identify them based on the reactions they observe.

Fourth graders improve their understanding of Graham's Law by using properties of gases to evaluate the rate of effusion of two compounds as they vaporize. They engage in a lab which elevates their understanding of the properties of gases.

In this science quiz worksheet, students complete a set of 20 true or false questions covering a variety of general science topics. An answer key is included.

The Bohr model and atomic orbitals. Using an element's position in the periodic table to predict its properties, electron configuration, and reactivity.

An explanation of the different types of atomic orbitals, how they are filled according to the Pauli Exclusion Principle, and how many electrons can fit in each electron shell.

An excellent tutorial that examines VSEPR and pairs of valence electrons. The valence shell electron pair repulsion concept is explored using animated models. Includes a VSEPR calculator. Use the toolbar on the left to navigate through...

Detailed explanation of Valence Shell Electron Pair Repulsion (VSEPR) Theory with examples and questions for the reader to check comprehension. Also includes step-by-step instructions for correctly building molecules using VSEPR Theory....

This page provides a thorough and comprehensible discussion of the structure of the atom. Includes helpful diagrams and instructions for filling electron shells, reading the Periodic Table, and drawing Lewis Structures.

[Free Registration/Login may be required to access all resource tools.] Covers valence shell electrons and inner shell electrons.

[Free Registration/Login Required] In this interactive you must place all of the students in their seats from back to front and see if you can figure out what element they would be if the rows of bus seats were the indicated electron...

Acting as a subtopic of the General Chemistry Virtual Textbook's section on Atoms and the Periodic Table, this site discusses repulsion of electron pairs. Diagrams and charts of the repulsion are also provided.

Presents examples of molecules that do not match the expected bond angles in the Valence-Shell Electron-Pair Repulsion Model. Requires Java.

Valence electrons are defined in terms of electron configuration.

Describes the Octet Rule as it pertains to the Groups 1-7 on the Periodic Table of Elements. It also provides a Sideways Periodic Chart With Electron Shell Numbers.

This lesson will explain how to identify the number of valence electrons an element has based on its position on the periodic table. It is 3 of 3 in the series titled "Identifying Valence Electrons."

This site from the Purdue University provides an overview of atomic orbitals and how quantum numbers specify these orbitals. Includes a model that can be rotated and examined in 3D. Includes learning exercises and answers.

Presents exercises where students can check their understanding of the Valence-Shell Electron-Pair Repulsion Model by predicting what a molecular shape will be. Requires Java.

Explains the principles of the Valence-Shell Electron-Pair Repulsion Model, and gives examples of the geometry. Requires Java.

[Free Registration/Login may be required to access all resource tools.] Covers energy levels of atoms, their relation to orbitals, and the significance of electrons at different energy levels.

This interactive periodic table developed for Teachers' Domain provides detailed information about the chemical properties of elements and illustrates the electron configurations that determine those characteristics.

[Free Registration/Login may be required to access all resource tools.] A collection of learning opportunities about electron orbitals. Includes videos, activities, discussion questions, and quizzes.

Why does the shape of a molecule matter? Learn about how the shape of the molecule not only determines the molecule's properties but also whether it reacts or not. This tutorial reviews of VSEPR and molecular geometry.