• 9-12: 4D/H8. The configuration of atoms in a molecule determines the molecule's properties. Shapes are particularly important in how large molecules interact with others.

• 4D (6-8) #1.  All matter is made up of atoms, which are far too small to see directly through a microscope. The atoms of any element are alike but are different from atoms of other elements. Atoms may stick together in well-defined molecules or may be packed together in large arrays. Different arrangements of atoms into groups compose all substances.
• 4D (6-8) #5.  Scientific ideas about elements were borrowed from some Greek philosophers of 2,000 years earlier, who believed that everything was made from four basic substances: air, earth, fire, and water. It was the combinations of these "elements" in different proportions that gave other substances their observable properties. The Greeks were wrong about those four, but now over 100 different elements have been identified, some rare and some plentiful, out of which everything is made. Because most elements tend to combine with others, few elements are found in their pure form.
• 4D (6-8) #6.  There are groups of elements that have similar properties, including highly reactive metals, less-reactive metals, highly reactive nonmetals (such as chlorine, fluorine, and oxygen), and some almost completely nonreactive gases (such as helium and neon). An especially important kind of reaction between substances involves combination of oxygen with something elseÑas in burning or rusting. Some elements don't fit into any of the categories; among them are carbon and hydrogen, essential elements of living matter.
• 4D (9-12) #1.  Atoms are made of a positive nucleus surrounded by negative electrons. An atom's electron configuration, particularly the outermost electrons, determines how the atom can interact with other atoms. Atoms form bonds to other atoms by transferring or sharing electrons.
• 4D (9-12) #9.  The rate of reactions among atoms and molecules depends on how often they encounter one another, which is affected by the concentration, pressure, and temperature of the reacting materials. Some atoms and molecules are highly effective in encouraging the interaction of others.

This interactive periodic table is one of the web's most extensive reference resources on the elements and their properties. Click on any element in the table to see a spectrum of information, including electron configuration, atomic and nuclear properties, and a brief history of each element.

• Physical Sciences K-8 Properties of Matter Unit
• Physics First Properties of Matter Unit
• Conceptual Physics Properties of Matter Unit
• Algebra-Based Physics Properties of Matter Unit
• AP/Calculus-Based Physics Properties of Matter Unit

This interactive periodic table is one of the web's most extensive reference resources on the elements and their properties. Click on any element in the table to see a spectrum of information, including electron configuration, atomic and nuclear properties, and a brief history of each element.

• Physical Sciences K-8 Elements and the Periodic Table Unit
• Physics First Elements and the Periodic Table Unit
• Conceptual Physics Elements and the Periodic Table Unit
• Algebra-Based Physics Elements and the Periodic Table Unit
• AP/Calculus-Based Physics Elements and the Periodic Table Unit