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Compare-Contrast-Connect: The History of Mendeleev's Table

NGSS Science and Engineering Practices:

NGSS Crosscutting Concepts:

NGSS Disciplinary Core Ideas:

Pre-1869

When scientists began to classify and organize the elements, about 63 elements were known. Many, like gold, silver, tin, copper, lead, and mercury had been known since antiquity. Phosphorus was discovered in 1669. Many more elements were discovered over the next 220 years. During this time, scientists determined the masses of the individual elements. They learned many other chemical properties by methodically exposing individual elements to various chemicals and observing the reactions. As more information was learned about individual elements, scientists wanted to organize the elements in a useful way. From 1817 through the time of Mendeleev, many scientists made important contributions to what would become the modern periodic table.

  • In 1817, Johann Dobereiner noticed that the atomic mass of strontium was halfway between those of calcium and barium. These three elements had similar properties. Dobereiner discovered more of these sets of three and called it the Law of Triads.
  • In 1862, A. E. Beguyer de Chancourtois arranged the elements on a cylinder, with the elements wrapping around the cylinder. On this three-dimensional table, the elements lined up in vertical columns.
  • In 1863, John Newlands published a table with elements arranged in groups of eight (SF Fig. 2.11), proposing the elements followed the Law of Octaves.

<p><strong>SF Fig. 2.11.</strong> John Newlands’ table of elements followed the Law of Octaves (1863). Each row contained eight elements.</p><br />

 

Newlands’ table was not well received because two elements were in the same box in several spots on his table. In the late 1800s, Lothar Meyer was developing a periodic table at the same time as Mendeleev. Meyer’s periodic table was very similar to Mendeleev’s, but because it was published after Mendeleev’s, Mendeleev got most of the credit. Mendeleev has been called the “father of the periodic table”.

 

Mendeleev’s Table

Dmitri Mendeleev was born in 1834 in Russia. He was the youngest of 13 (or 11, 14, or 17, depending on the source) children. Mendeleev was interested in many fields of science and studied a wide variety of science topics throughout his life. As a child he learned about chemistry in his mother’s glassblowing factory. At university, he earned an advanced degree in chemistry while training as a teacher. While teaching chemistry as a professor at the University of St. Petersburg, Mendeleev felt that there were no adequate textbooks for teaching chemistry, so he began to write his own. While working on his textbook from 1868–1870, he began formulating ideas for a way to organize the elements. Mendeleev’s fist attempt to organize the elements is seen in SF Fig. 2.12. In his first periodic table Mendeleev arranged the elements by their mass and other chemical properties. At the time, the underlying chemical structure of atoms was not known.

 

<p><strong>SF Fig. 2.12.</strong> Mendeleev’s first effort to organize the elements (1868), the numbers are the masses of the elements</p><br />

 

Mendeleev expanded his periodic table to include all the elements known at the time. This version of the periodic table was published in 1869. A draft of this periodic table, in Mendeleev’s own writing, is seen in SF Fig. 2.13.

 

Mendeleev continued to refine his periodic table, publishing a new version (SF Fig. 2.14) in 1871. In this version, because of the patterns Mendeleev observed, he was able to notice holes in the patterns and predict that there were elements that had not yet been discovered that would fill those holes. Although some scientists were skeptical of this table, when new elements were discovered and some of Mendeleev’s predictions were supported by evidence, his periodic table became accepted by the scientific community. Further refinements to the periodic table have been made, including the addition of new elements, to create the modern periodic table.

 

<p><strong>SF Fig. 2.13.&nbsp;</strong>A draft of Mendeleev’s 1869 periodic table, written in his own handwriting</p><br />
<p><strong>SF Fig. 2.14.&nbsp;</strong>Mendeleev’s 1871 periodic table.</p><br />


 

The Importance of the Periodic Table

The periodic table is more than just a table of known elements. The name “periodic table” refers to the periodic nature of the arrangement of the elements. There are trends in the elements from left to right on the periodic table. Mendeleev knew that the atomic mass increased from left to right and assigned numbers to the elements based on his periodic table. As scientists continued to learn more about the atom, they learned that not just atomic mass and number, but other properties, like atomic size and atomic structure, also changed gradually from left to right on the periodic table. Scientists also discovered the links between atomic mass, the underlying structure of atoms, and the way elements behave. In modern times, we can use the periodic table to learn a lot of information about each element, as well as to make predictions about how elements will behave in certain situations.

 

Mendeleev’s Fame 

Mendeleev made many other contributions to chemistry, but was most widely known for the periodic table. He is highly regarded throughout the world, but especially in Russia and the former Soviet Union (SF Fig. 2.15 A–C). In the United States, the American Chemical Society is an organization that advances the study of chemistry. The equivalent organization in Russia is called the Mendeleev Russian Chemical Society. There is also a moon crater and an element, number 101, mendelevium, named after him.

 

<p><strong>SF Fig. 2.15.</strong> (<strong>A</strong>) Mendeleev stamp from the former Soviet Union.</p><br />
<p><strong>SF Fig. 2.15.&nbsp;</strong>(<strong>B</strong>) Mendeleev monument in Slovakia. The elements are arranged around Mendeleev’s likeness.</p><br />
<p><strong>SF Fig. 2.15.&nbsp;</strong>(<strong>C</strong>) Commemorative Russian coin from Mendeleev’s 175<sup>th</sup> birthday.</p><br />

 

 

Question Set: 
  1. How did the organization of the periodic table change from the table John Newlands created to the modern periodic table? Compare and contrast each of the versions of the periodic table.
     
  2. One way to organize the elements is by an alphabetical list. When might this organization be useful? When might the periodic table be more useful?
     
  3. Isaac Newton wrote “If I have seen a little further, it is by standing on the shoulders of giants.”
    1. What do you think Newton might have meant by this?
    2. How does this apply to Mendeleev? 
    3. Do you think scientists make discoveries or contributions on their own? Why or why not?

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Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.