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 ...

14 words that defined 2020 4 A shape with 21 sides is called a icosikaihenagon. 5 21 is the atomic number of the chemical element scandium. 6 The summer and winter solstices take place (usually ...

118 Elements and Their Symbols and Atomic Numbers: The periodic table is a well-organized chart that contains all the known elements in the universe.These elements are building blocks of matter ...