The periodic table, also called the periodic table of elements, is an organized arrangement of the 118 known chemical elements. The chemical elements are arranged from left to right and top to bottom ...

Thank you for bringing to my attention the recent International Union of Pure & Applied Chemistry report “Atomic weights of the elements 2009” (C&EN, Dec. 20 ...

For the first time those little numbers that appear beneath some of the commonest elements in the periodic table boxes are about to change from a single value to an interval of numbers An ...

Mass spectrometry—a technology that is constantly being made more accurate and reliable—is used every two years to revise the standard atomic weights of select elements. This year, the International ...

FOR the past thirty years, beginning with F. W. Aston's observation of small deviations from his whole-number rule, the mass spectrograph has been used for determining atomic masses. One of the first ...

The relative atomic masses of elements are proportional measures. For example, the Ar for helium is 4.0, and the A r for carbon is 12.0. This means that carbon atoms have three times the mass of ...

A schematic diagram of proton and neutron distributions for mirror nuclei argon-31 and aluminum-31. Left side is the weakly bound proton-rich nucleus argon-31, which is predicted to exhibit a ...

Scientists have precisely measured two unstable atomic nuclei that play a crucial role in explosive X-ray bursts on neutron ...

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 ...