The covalent radius (a measure of how large individual atoms are) shows different trends if you are moving ... As you move from left to right across the periodic table, atoms have more electrons ...

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

Although the telluric screw did not correctly display all the trends that were known at the time, de Chancourtois was the first to use a periodic arrangement of all of the known elements, showing that ...