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The Periodic Table's story began with early attempts to categorize elements by their properties. Mendeleev's genius in 1869 arranged them by atomic weight, even predicting missing elements based on gaps and their properties. His foresight was confirmed, solidifying the concept. Later, atomic number took the lead, and the table evolved with discoveries of isotopes, neutrons, and new elements. Today, it stands as a testament to scientific collaboration, constantly adapting to our evolving understanding of the matter that makes up our world.
1.
Around 330 BCE, the Greek philosopher Aristotle proposed that everything is composed of a mixture of four fundamental elements: earth, water, air, and fire.
These ideas were also present in other ancient traditions, including Indian philosophy.
By the time of alchemy, a few additional elements were known, such as zinc, arsenic, antimony, and bismuth. Platinum was also known to pre-Columbian South Americans but reached Europe only in the 16th century.
2.
The history of the periodic table is intertwined with the discovery of chemical elements.
Hennig Brand, a German merchant, was the first recorded person to discover a new element. In his quest for the mythical philosopher’s stone, he accidentally produced phosphorus from distilled human urine around 1669.
Brand called this substance “cold fire.”
3.
The Scientific Revolution and Industrial Revolution spurred interest in classifying elements.
1800-1849: During this period, 22 elements were discovered, influenced by atomic theory and scientific advancements.
1800-1849: During this period, 22 elements were discovered, influenced by atomic theory and scientific advancements.
4.
Dmitri Mendeleev, a Russian chemist, is renowned for creating the first periodic table in 1869.
He arranged elements by increasing atomic number, creating rows (periods) and columns (groups) based on recurring properties (periodicity).
Mendeleev’s table allowed for predictions of undiscovered elements and their properties.
5.
Antoine-Laurent de Lavoisier, Johann Wolfgang Döbereiner, John Newlands, and Julius Lothar Meyer also made significant contributions.
In the mid-20th century, Glenn T. Seaborg expanded the periodic table to include transuranium elements.
The periodic table remains a powerful tool for understanding the properties and reactivity of elements, as well as a window to the universe.
The Periodic Table is organised in rows and columns. The rows are called periods. The columns are called groups.
The atoms are organised so that, as you read across each row (period) from left to right, the atoms increase in mass. Hydrogen atoms have the smallest mass, then helium atoms, then lithium atoms.
Seeing chemical elements arranged in the modern periodic table is as familiar as seeing a map of the world, but it was not always so obvious. The creator of the periodic table, Dmitri Mendeleev, in 1869 began collecting and sorting known properties of elements, like he was playing a game, while traveling by train. He noticed that there were groups of elements that exhibited similar properties, but he also noticed that there were plenty of exceptions to the emerging patterns.
Incredibly, instead of giving up, he tried altering the measured property values to better fit the patterns! He also predicted that certain elements must exist which didn’t at the time – again, in an effort to get the patterns in his "game" to work out. There were plenty of skeptics and it took years to gain international acceptance, but once newly-discovered elements matched the ones that Mendeleev predicted, his patterns could not be dismissed. In addition, some of the properties that he "fudged" were later recalculated and found to be much closer to his predictions.
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