Exercises
I. Word-study.
Give Russian equivalents to the following words, word combinations from the text:
to claim, measurement, to constitute combinations of solutes and solvents, to double search, respectively, revolutionary generalization, to be foreshadowed, accidental, to designate, prophetically, a reliable indicator.
II. Comprehension check-up.
1) Answer the following questions.
1. What kind of family was Mendeleev born in?
2. What was the foundation of the “Periodic Law”?
3. When did Mendeleev start to develop a new theory of the origin of petroleum?
4. What elements did Mendeleev designate with empty spaces in his chart?
5. Were there any other scientists’ attempts to find a system to order the elements?
2) Find information about Mendeleev:
a) his awards
b) his educational background
c) his role in chemistry
d) the beginning of his career
III. Say what new information about Mendeleev you have learnt. Marie sklodowska curie (1867-1934)
The
remarkable story of the discovery of radium began with Henri
Becquerel's discovery in 1896 of the spontaneous emission of ionizing
radiation (later identified as α-, β-,
and
γ-
rays)
from uranium and its compounds. Rontgen in Germany had described
X-rays a few months earlier. Curie, who had married the French
physicist Pierre Curie in 1895, began an investigation of the
properties of these "uranium" or "Becquerel" rays
for her doctoral thesis.
Marie Sklodowska's marriage to Pierre Curie initiated one of the greatest scientific collaborations of the nineteenth and early twentieth centuries. As their daughter Irene (who also married and worked with a nuclear physicist, Frederic Joliot) later wrote: "during the eleven years of their life together, they never left each other's side, neither during their work nor on their vacations". Marie or "Manya" was the daughter of a Polish school teacher. She had endured great hardships, working as a governess, in order to save money to study at the Sorbonne in France. Her perseverance under difficult conditions, both personal and scientific, was characteristic of her entire life and career.
Curie began her study of uranium rays by measuring a number of elements, minerals, and compounds for ionizing activity with a sensitive electrometer designed by Jacques and Pierre Curie, the quartz piezo-electroscope. She studied thorium, which also emitted Becquerel rays, and proposed the term "radioactivity" for the optical and magnetic properties observed by Becquerel, which were unaffected by chemical combination with other elements. Curie examined such minerals as clevite, chalcolite, carnotite, and autunite and determined that those which displayed significant radioactivity commonly contained either uranium or thorium. She also discovered that a uranium-bearing ore, pitchblende, released up to 4 times more radioactivity than uranium oxide and suspected an unknown element. With several tons of ore obtained from the Austrian government, Curie, joined by Pierre, began the laborious process of chemically isolating the source of the extraordinary radiation. They extracted an unstable substance in 1898 and proposed the name "polonium," after Curie's homeland. A second substance was isolated and spectroscopic measurement (each element absorbs and emits a characteristic spectrum of light) by Eugene Demarcay indicated that this was not a known element. They suggested the name "radium" for the new element. In 1902 the Curies isolated a decigram of pure radium chloride by fractional crystallization and received substantial funds from the French Academy of Science for the extraction of radioactive elements. In the meantime, Andre Debierne had isolated another previously unknown radioactive element, actinium, from pitchblende in 1900. The actual discovery of radium, therefore, consisted of a mixture of brute determination, intuition, and an hypothesis with very few supporting facts, as Curie later explained: "our research method could only be based on the radioactivity of the hypothetical substance, because we were ignorant of any other of its properties".
The Curies shared the 1903 Nobel Prize with Becquerel for their work on radium and radioactivity. After Pierre Curie was fatally mangled by a passing carriage in 1906, Curie was offered the chair at the Sorbonne which had been created for her husband. Curie continued her efforts to determine an accurate atomic weight for radium. Radium, which had quickly become the most expensive substance in the world, would soon become medically and commercially valuable with the development of radiotherapy, or curietherapy as it was called in France, for cancer. Like many new pharmaceuticals introduced into western culture, such as opium, tobacco, and cannabis, radium was hailed as a panacea for an astonishing number of diseases, before the devastating effects of large doses of it were illustrated by the deaths of watch dial painters in the 19205 exposed to radium-based paints.
Curie was awarded a second Nobel Prize in 1911 for her continuing work on radium. Several days later, she was denied membership in the Academic des Sciences, demonstrating the considerable professional obstacles encountered by women scientists during the period. French public sentiment concerning this foreign-born and unconventional woman was ambivalent, especially after the publication of letters in 1911 exposing an affair between Curie and Paul Langevin, who was married at the time.
In 1912, construction began on the Institut du Radium in Paris. During World War I, Curie organized a fleet of trucks with portable x-ray units for field use and later wrote Radiology and War (1921). Marie Meloney, a U.S. journalist, organized a donations campaign to produce a gram of radium for Curie's laboratory. In 1921, President Warren G. Harding personally presented Curie with the key to a lead-lined casket for housing the gift. Curie raised two daughters, the writer Eve and the physicist Irene Joliot-Curie, who along with her husband Frederic made important advancements in artificial radioactivity and nuclear fission. In 1934, Curie died from complications from the years of radiation exposure to the element which she had discovered.