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Noble Gases

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Official Audio Prompt

Discovered around the end of the 19th century, the noble gases are the most stable group of the chemical elements. The six gases: helium, neon, argon, krypton, xenon, and radon have a myriad of modern uses. When they were first discovered, their strangely stand-offish properties were a mystery. Uniquely stable, they seemed to participate in no chemical reactions. But by understanding the stability of the noble gases, physicists discovered the key to chemical bonding itself. Dmitri Mendeleev added the noble gases to his periodic table in 1902, where he arranged the elements in rows and columns according to their atomic weight. Mendeleev was able to see repeating (or periodic) patterns in their properties. The noble gases appeared regularly in the periodic table, occurring in every eighth position, at least amongst the lighter elements. Physicists struggled to find a model that would explain this curious observation. What was the significance of the number eight?

Sample Answer & Audio Transcript

Discovered around the end of the 19th century, the noble gases are the most stable group of the chemical elements. The six gases: helium, neon, argon, krypton, xenon, and radon have a myriad of modern uses. When they were first discovered, their strangely stand-offish properties were a mystery. Uniquely stable, they seemed to participate in no chemical reactions. But by understanding the stability of the noble gases, physicists discovered the key to chemical bonding itself. Dmitri Mendeleev added the noble gases to his periodic table in 1902, where he arranged the elements in rows and columns according to their atomic weight. Mendeleev was able to see repeating (or periodic) patterns in their properties. The noble gases appeared regularly in the periodic table, occurring in every eighth position, at least amongst the lighter elements. Physicists struggled to find a model that would explain this curious observation. What was the significance of the number eight?
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