The Periodic Table is a well-organized chart that contains all 118 known elements in the universe. These elements are the ...

The reactions of elements are related to the number of electrons ... have a full outer electron shell, so are very stable. See the study guide on groups in the periodic table for more information.

In this activity, students will use the online periodic table, ptable.com, to investigate a number of chemistry concepts. Students will use this online resource to explore information about the ...

The picture shows a close-up of one carbon atom. A hydrogen atom has one proton as the nucleus and one electron in the region outside the nucleus. The electron and proton are attracted to each other.