Yellow star (sun) schematics showing its inner structure

Observing the Sun: Its Structure and Layers

November 18, 2021

Because of its closeness to the Earth, the Sun is the most thoroughly studied star. Our knowledge of the Sun and the observations of distant stars help us understand the life cycles of other stars. […]

The position of fluorine in the periodic table.

Completing Mendeleev’s Periodic Table

August 22, 2021

The periodic table had clear gaps that required predictions, and many of those predictions were filled when new elements predicted by Mendeleev were subsequently discovered. […]

An image of pure antimony.

The Concept of Chemical Elements

August 22, 2021

Throughout the 18th and 19th centuries, chemists identified more and more new chemical elements, adding to the dozen or so elements that had been known to the ancients. […]

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