Molecular and Atomic Mass of Elements: There are various concepts in chemistry that require a basic understanding to see the bigger picture. One such knowledge is knowing the key terminologies and ...

Atomic Number and Mass Number of Elements: Atoms are the building blocks of matter. They are responsible for the format of all living and non-living things. Understanding their molecular structure and ...

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 ...

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 ...

I was surprised that C&EN would devote two columns to the letter by Harvey Carroll on the matter of atomic weight versus atomic mass (C&EN, Jan. 24, page 4). I realize the majority of the informed ...

Discover the history, structure, and importance of the periodic table of elements, from Mendeleev’s discovery to modern scientific applications. When you purchase through links on our site, we may ...

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 ...

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 ...

Precise values for the masses of the nuclei of the simplest atoms, such as hydrogen and helium, are crucial for experiments targeting big unsolved problems in physics. A technique known as ...

Standard atomic weights, those numbers emblazoned under the elements on the periodic table, were once thought of as unchanging constants of nature. But researchers have tweaked the atomic weights of ...