Dmitry Ivanovich Mendeleyev is
known to be the creator of a periodic classification of the elements based on
their atomic weights andchemicalproperties.He is 19 probably well known in other countries as he is in the land of
his birth. The Periodic Law has crossed national boundaries and has become the
property of all nations, just like the works of Newton, Copernicus, Lomonosov,
Lavoisier, Darvin,- Pavlov, Lobachevsky and Einstein.
When speaking about the Periodic
Law, we cannot fail to stress its tremendous philosophical importance. It
reflects the dialectical interdependence between the structure of atoms and the
properties of elements, i. e., the transfer of quantity into a new quality. As
the charges of the atomic nuclei grow and their electron shells alter, we
notice changes in the physical and chemical properties of the elements. Like
all major discoveries the Periodic Law has a prehistory of its own. Before
Mendeleyev, several chemists made attempts to find the laws governing elements and
systematize them. But they based their research on erroneous concepts about the
main thmgs which determine the properties of elements, and so fail build up
a single comprehensive system.
It was only after gallium, scandium
and germanium were discovered, and after the properties of a number of elements
predicted by Mendeleyev were confirmed, that Mendeleyev at long last was
objectively recognized as the founder of the Periodic Law.
In the space of a
few years, Mendeleyev was elected an honorary member
of the American, Irish, Rome, Berlin, Belgian, Danish, Czech, Krakow and other
academies of sciences, a member of London and Edinburgh Royal societies and an
honorary doctor of Cambridge, Oxford and other universities. Altogether 150
scientific and educational institutions in various countries elected him as an
honorary member. In the Soviet Union, the All-Union Chemical Society, a number
of higher and secondary
schools and some industrial plants have been named after Mendeleyev. The USSR
Academy of Sciences and the Mendeieyev Society awarded the Mendeleyev prize and
the Mendeleyev gold medal for outstanding research work.
The significance of the now famous
table of Mendeleyev lay in his bold predictions that deficiencies or gaps in
his system were due to gross errors in the previous measurements of atomic
weights or simply to the fact that certain elements had not yet been
discovered. His specific and successful prediction of the existence of three
elements, gallium", scandium, and germanium, resulted in general
acceptance of his periodic
classification before the end of the nineteenth century.
Later on the element 101 having
been discovered, American scientists called it "mendelevium" to honor
Mendeleyev's name. Soviet scientists are hard at work trying to discover new
elements.
The rapid development of science
since the time of Mendeleyev has caused many widely accepted science theories
to become obsolete. Yet Mendeleyev's Periodic System continues to form the
basis for the most complex research to-dav.
EXERCISES
I.Read fluently:
the creator of a periodic
classification of the elements, the land of his birth, the property of all
nations, the transfer of quantity into a new quality, prehistory of its own, in
the space of a few years, before the end of the nineteenth century
II.Give synonyms for:
probably, boundary, to become,
importance, tremendous, i. e., quantity, alter, major, main, number, concept,
confirm, honor, recognize, predict, certain, rapid, to continue.
III.Give antonyms for:
major, efficiency, success, slow,
result in, obsolete, complex, accept,charge.
