The periodic table of chemical elements, often called the periodic table, organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic ...

But how many of these elements do you know? Test your knowledge and compete with other Live Science readers to see who can ...

as elements. But these are very different from the isolated atoms depicted on the periodic table. That’s why some chemists think we should make a distinction between the abstract chlorine on the ...