Students use the terms isotope, atomic number, mass number, and atomic mass. Atomic Theory: Structure of the Atom: Students use the terms isotope, atomic number, mass number, and atomic mass to ...

For example, the atomic number of chlorine is 17. Every chlorine atom has 17 protons and 17 electrons. It has 17 positive charges and 17 negative charges, meaning that it is neutral overall. Atoms of ...

How does one go about measuring the mass of an object? Mass is defined as the amount of matter an object contains. This is very different from weight, of course, as the mass of our object would remain ...

Most of the units we rely on are based on precision microscopic measurements—regular fluctuations in certain atoms define one second of time, for example. A major exception to this is the basic unit ...

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 ...

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 ...

In a feat of modern-day alchemy, atom tinkerers have fooled hydrogen atoms into accepting a helium atom as one of their own. The camouflaged atom behaves chemically like hydrogen, but has four times ...