The periodic table was arranged by atomic mass, and this nearly always gives the same order ... and this explained further why Moseley’s X-rays corresponded so well with atomic number. The idea behind ...

The atomic number of tellurium is 52 and the atomic number of iodine is 53, so these elements are in the correct order in the modern periodic table.

Two elements in group 1 of the periodic table are lithium and sodium. Very small pieces of lithium and sodium were reacted separately with water. In the periodic table, the group 7 elements and ...