Development of the Periodic Table (I couldn't find the exact dates for all of these events so that is why they all say 1st Jan)
By lollyhong123
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Period: to
the development of the periodic table
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Johann Dobereiner (1780-1849)
Dobereiner grouped the known elements based on similaritys. -
In 1829 Dobereiner proposed the Law of Triads
it was found that certain elements could be grouped together.When arranged in order of atomic mass the elements usually ended up in groups of 3. The middle element in the triad had an atomic weight that was the average of the other two members. -
Alexandre Beguyer de Chancourtois (1820-1886) published a list of all the known elements.
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Law of Octaves
English chemist John Newlands (1837-1898), having arranged the 62 known elements in order of increasing atomic weights, noted that after interval of eight elements similar physical/chemical properties reappeared. Newlands was the first to formulate the concept of periodicity in the properties of the chemical elements. In 1863 he wrote a paper proposing the Law of Octaves. -
Mendeleev's Periodic Table
Russian chemist Dimitri Mendeleev (1834-1907) proposed arranging elements by atomic weights and properties. -
Mendeleev's periodic table (revised!)
Mendeleev revised the 17-group table with eight columns. This table showed similarities in an entire network of vertical, horizontal, and diagonal relationships. The table contained gaps but Mendeleev predicted the discovery of new elements. -
Discovery of Argon
Lord Rayleigh reported the discovery of a new gaseous element named argon. This element did not fit any of the known periodic groups and therefore raised questions about why it was an odd one out. They realised there must be more elements that fitted into a group with this one. -
Discovering more inert gases
William Ramsey followed by discovering the remainder of the inert gases and positioning them in the periodic table. -
Rayleigh and Ramsey's Nobel Prizes
Rayleigh (physics) and Ramsey (chemistry) were awarded Nobel prizes in 1904. -
Nobel Prize for Chemistry
In this year Mendeleev came within one vote of receiving the Nobel Prize in chemistry. -
Moseleys' Work
When Moseley arranged the elements according to increasing atomic numbers and not atomic masses, some of the inconsistencies associated with Mendeleev's table were eliminated. -
Noble Gas compounds
The first inert gas compound was made in 1962 (xenon tetrafluoride) and many have been made since then. The inert gases are more commonly known as the Noble gases nowadays. -
The Periodic Table today
Today All together there are 117 elements on the periodic table, 94 of which occur naturally on earth.
