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

The periodic table was arranged by atomic mass, and this nearly always gives the same order as the atomic number. However, there were some exceptions (like iodine and tellurium, see above), which didn ...

The Periodic Table is an amazing chemistry tool that is organized with elements in order of increasing atomic number. The properties of the element change as you move across the row, but are similar ...

As you move from left to right across the periodic ... table, atoms have more electrons in their outer energy level and more protons in their nucleus. The greater attraction between the increased ...