CHEMISTRY
People manipulated substances found in nature long before chemistry became an organized pursuit. Ancient weapons, ceramics and other artifacts demonstrate a practical knowledge of chemical reactions despite little understanding of how they worked.
Early philosophers theorized that everything was made of foundational substances the earth, air water and fire. Overlap between chemistry as modem science and the durable pseudoscience known as alchemy remained until the scientific revolution was well under way. Even Sir Isaac Newton toyed with the idea of synthesizing gold. So did Robert Boyle,
considered a founder of modern chemistry in the 1600s for his intense experimental approach and his rejection of the old Greek ideas in favor of a more universal theory of matter
Chemistry in Boyle's day focused on the study of gases Boyle's law. for example, describes the inverse relation between the volume and pressure of a gas. Over time, particular attention turned to the process of combustion, By the 18th century, theories about combustion focused on phlogiston, hypothesized by German physician George Ernst Stahl as the substance that allowed things to burn
The phlogiston theory did not satisfy Antoine Lavoisier a French chemist
who used advances in measurement to analyze the constituent parts of different substances. He noticed that sulfur and phosphorus weighed more after combustion than before, & finding inconsistent with the idea that their phlogiston had been consumed. English chemist Joseph Priestley had been experimenting with a gas whose presence made candles burn more brightly and whose absence killed small animals Lavoisier identified the gas, which he called oxygen, as the key to combustion and breathing. The combined work of Lavoisier. Priestley, English aristocrat Henry Cavendish, and Scottish chemist Joseph Black set the stage for modern atomic and chemical theory
Late 19th and early 20th century advances in physics helped answer an other basic question: Why do atoms stick together in the first place? Discovery of the electron focused the search on an electrical basis for the bond. Niels Bohr's quantum mechanics and Linus Pauling's chemical research indicated that an atom's furthermost, or valence, electrons control its ability to combine with other atoms. Advances in analytical equipment and industrial methods produced a veritable explosion of practical discoveries and synthetic chemical inventions that continues to this day, spinning fabrics and plastics from petroleum and HOMAS EDISON'S LABORATORY, circa 1915, in West Orange, New Jersey, where the unraveling the complicated chemical processes that support life.
HOW DOES THE PERIODIC TABLE WORK?
Charting the elements for a textbook in the late 1860s, Russian chemist Dmitry Mendeleyev noticed similarities in groups of elements based on their atomic weight: Each element resembled the eighth to follow it. That insight led him to outline the periodic table still in use today. By arraying elements in rows and
columns, placing like substances in vertical groups, Mendeleyev accurately predicted that other elements would eventually be discovered. Later the chart was reorganized to reflect the proton count in an atom's nucleus an element's atomic number. It contains 118 elements, as many as 90 of which occur naturally.
RICHARD SMALLEY
The challenge inherent in Dmitry Mendeleyev's first, incomplete periodic table remains ongoing, and in 1985 Richard Smalley (1943-2005) was among a trio of chemists who discovered a new and potentially revolutionary form of natural carbon. Vaporizing graphite rods with lasers in helium gas produced circular, beautifully symmetrical structures containing 60 carbon atoms.
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