The periodic table of elements (often known simply as the periodic table) has been helping scientists with their work for a little over 150 years. The handy visual reference guide organizes known ...

Accompanying Lesson Plan: Lesson 3.2: Finding Volume—The Water Displacement Method The chart shows that atomic size and mass for the first 20 elements in the periodic table. The size of the atoms and ...

It's important to use the names and chemical symbols for the first 20 elements in the periodic table, as well as the elements in groups 1 and 7.

See if you can organize the first 25 elements of the periodic table in order in the quiz below. The periodic table as we know it is widely credited to Dmitri Mendeleev, a Russian chemist who kept ...