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 ...

At the far end of the periodic table is a realm where nothing is quite as it should be. The elements here, starting at atomic number 104 (rutherfordium), have never been found in nature. In fact, they ...

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 ...

The modern periodic table, arranged in rows and columns, was first introduced by Dmitri Mendeleev in 1869. At the time, it included the known elements and their properties, but Mendeleev predicted ...

It is an icon of natural science and hangs in most chemistry classrooms: the periodic table of elements, which is celebrating its 150th birthday this year. The tabular overview is closely linked to ...

Antimony (Atomic Number 51) is an Essential Element for US Defense. 80% of it Comes From China. Most of the rest comes from this one mining company — and it’s incidental to the precious metals this ...

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 ...

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) ...

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 ...