Chemical Element and Atomic Weights
The history of the periodic table reflects over a century of growth in the understanding of chemical properties, and culminates with the publication of the first actual periodic table by Dmitri Mendeleev in 1869.[1] While Mendeleev built upon earlier discoveries by such scientists as Antoine-Laurent de Lavoisier and Stanislao Cannizzaro, the Russian scientist is generally given sole credit for development of the actualperiodic table itself.
The table itself is a visual representation of the periodic law which states that certain properties of elements repeat periodically when arranged by atomic number. The table arranges elements into vertical columns (groups) and horizontal rows (periods) to display these commonalities.
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Elemental ideas from ancient times People have known about some chemical elements like gold, silver and copper from antiquity, as these can all be discovered in nature in native form and are relatively simple to mine with primitive tools.[2] However, the notion that there were a limited number of elements from which everything was composed originated with the Greek philosopher Aristotle. About 330 B.C Aristotle proposed that everything is made up of a mixture of one or more of four "roots" (originally put forth by the Sicilian philosopher Empedocles), but later renamed elements by Plato. The four elements were earth, water, air and fire. While the concept of an element was thus introduced, Aristotle's and Plato's ideas did nothing to advance the understanding of the nature of matter.
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Age of Enlightenment Hennig Brand was the first person recorded to have discovered a new element. Brand was a bankrupt German merchant who was trying to discover the Philosopher's Stone — a mythical object that was supposed to turn inexpensive base metals into gold. He experimented with distilling human urine until in 1649[3] he finally
The table itself is a visual representation of the periodic law which states that certain properties of elements repeat periodically when arranged by atomic number. The table arranges elements into vertical columns (groups) and horizontal rows (periods) to display these commonalities.
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Elemental ideas from ancient times People have known about some chemical elements like gold, silver and copper from antiquity, as these can all be discovered in nature in native form and are relatively simple to mine with primitive tools.[2] However, the notion that there were a limited number of elements from which everything was composed originated with the Greek philosopher Aristotle. About 330 B.C Aristotle proposed that everything is made up of a mixture of one or more of four "roots" (originally put forth by the Sicilian philosopher Empedocles), but later renamed elements by Plato. The four elements were earth, water, air and fire. While the concept of an element was thus introduced, Aristotle's and Plato's ideas did nothing to advance the understanding of the nature of matter.
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Age of Enlightenment Hennig Brand was the first person recorded to have discovered a new element. Brand was a bankrupt German merchant who was trying to discover the Philosopher's Stone — a mythical object that was supposed to turn inexpensive base metals into gold. He experimented with distilling human urine until in 1649[3] he finally