The position of fluorine in the periodic table.
Chemistry

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.
Chemistry

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. […]

Different isotopes of carbon and their atomic structure.
Biology

Carbon 14 Dating: Complications and Mitigations

September 13, 2020

Carbon 14, a radioactive isotope of carbon, is used to measure the age of an ancient fossil. Since the depleting carbon 14 content is present in all the living things, it can be reliably used to measure the age of a fossil. […]

A closeup view of old tree rings full of carbon content.
Biology

Using Carbon 14 Dating

September 13, 2020

Carbon 14, a radioactive isotope of carbon, is used to measure the age of an ancient fossil. Carbon 14 works on the basis of carbon 14 depletion ratio to other carbon isotopes, which starts only after the death of the organic matter. […]

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