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 ...

The periodic table The periodic table is a chart ... The three common Group 7 elements are chlorine, bromine and iodine. The word ‘halogen’ means 'salt former'. Group 0 and testing ions ...

So about 100 elements in the periodic table, arranged according to their ... to a few elements ending up in the wrong columns, like iodine and tellurium. Tellurium has a greater atomic weight ...