Nineteen elements on the periodic table — including gold, cadmium, arsenic and aluminum — are getting their atomic weights adjusted. The International Union of Pure and Applied Chemistry (IUPAC) ...

Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

IN a recent number of NATURE (February 14, p. 367) Dr. Barkla gave reasons, based on experiments in connection with secondary Röntgen radiation, for assigning to nickel a new atomic weight. Dr. Barkla ...