Dmitri
Mendeleev
Dmitri
Mendeleev is known as the father of the periodic chart of elements.
He founded a method that enabled later scientists to discover
elements that hadn't even been heard of yet according to the properties
of the surrounding elements.
Dmitri
Mendeleev was a Russian chemist who in the 1800's, became famous
for the discovery one of the basic principals of chemistry. He
collected thousands of facts about the 63 elements that were in
existence and had already been discovered at that time. Scientists
working before him had concluded that groups of elements had similar
chemical and physical properties. His hunch was that a pattern
or order must exist in all elements. He wrote a book recording
all of his discoveries. He called it properties of chemistry.
He wanted to be the first scientist to put the elements into an
organized order. He did this according to many factors but mainly
according to the order of increasing atomic gas. He was surprised
and pleased to find that the elements were also organized in other
ways. He called this chart that he had organized the periodic
chart of elements.
Dmitri
Ivanovich Mendeleev (1834-1907), the youngest of 17 children was
born in the Siberian town of Tobol'sk where his father was a teacher
of Russian literature and philosophy.
Mendeleev was not considered an outstanding student in his early
education partly due to his dislike of the classical languages
that were an important educational requirement at the time even
though he
showed prowess in mathematics and science. After his father's
death, he and his mother moved to St. Petersburg to pursue a university
education. After being denied admission to both the University
of
Moscow and St. Petersburg University because of his provincial
background and unexceptional academic background, he finally earned
a place at the Main Pedagogical Institute (St. Petersburg Institute).
Upon graduation, Mendeleev took a position teaching science in
a gymnasium. After a time as a teacher, he was admitted to graduate
work at St. Petersburg University where he earned a Master's degree
in
1856. Mendeleev so impressed his instructors that he was retained
to lecture in chemistry. After spending 1859 and 1860 in Germany
furthering his chemical studies, he secured a position as professor
of
chemistry at St. Petersburg University, a position he retained
until 1890. While writing a textbook on systematic inorganic chemistry,
Principles of Chemistry, which appeared in thirteen editions the
last
being in 1947, Mendeleev organized his material in terms of the
families of the known elements which displayed similar properties.
The first part of the text was devoted to the well known chemistry
of the
halogens. Next, he chose to cover the chemistry of the metallic
elements in order of combining power -- alkali metals first (combining
power of one), alkaline earths (two), etc. However, it was difficult
to
classify metals such as copper and mercury which had multiple
combining powers, sometimes one and other times two. While trying
to sort out this dilemma, Mendeleev noticed patterns in the properties
and
atomic weights of halogens, alkali metals and alkaline metals.
He observed similarities between the series Cl-K-Ca , Br-/Rb-Sr
and I-Cs-Ba. In an effort to extend this pattern to other elements,
he created a
card for each of the 63 known elements. Each card contained the
element's symbol, atomic weight and its characteristic chemical
and physical properties. When Mendeleev arranged the cards on
a table in
order of ascending atomic weight grouping elements of similar
properties together in a manner not unlike the card arrangement
in his favorite solitaire card game, patience, the periodic table
was formed. From
this table, Mendeleev developed his statement of the periodic
law and published his work On the Relationship of the Properties
of the Elements to their Atomic Weights in 1869 (view a copy of
Mendeleev's
table as published in Annalen supple. VIII, 133 (1871). The advantage
of Mendeleev's table over previous attempts was that it exhibited
similarities not only in small units such as the triads, but showed
similarities in an entire network of vertical, horizontal, and
diagonal relationships. In 1906, Mendeleev came within one vote
of being awarded the Nobel Prize for his work.
Good links:
Web-elements
History
of periodic law
periodic
table of elements
bibliography