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 ...

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 ...

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 ...

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 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 ...

More than 40 years after scientists first detonated a nuclear device in the Trinity test, composer and conductor James Yannatos assembled over 350 musicians for an unusual memorial. In April 1986, 90 ...