The Inert Gases

The Discovery of Radium

Say what connection the following dates and word combinations are mentioned in.

1885, lectures in general chemistry, D. Mendeleyev, in the chair of analytical and organic chemistry, mark the beginning, found the time for, 1911, small laboratory, activated charcoal, to keep door open, principal paths, army of chemists

13. Name and characterize the main periods of the scientist’s activity, both administrative and scientific ones.

14. Read the text. Give Russian equivalents to the underlined word-combinations:

In 1896, Antoine Bacquerrel learnt the fluorescence shown by uranic salts such as potassium uranyl sulphate made an interesting observation that a wrapped photographic plate was being affected by these salts even in the dark. It appeared therefore, that a new type of radiation was being emitted. The radiation passed through a black paper and affected a photographic plate.

Interested in the discovery Marie Curie suggested that the reason for the phenomenon was in the uranium atom as the other elements by themselves in uranium salts never emitted any rays.

Marie Curie began to test all sorts of substances for “rays” and soon discovered that thorium compounds were also active.

It was found that this radioactivity is an atomic property with an intensity directly proportional to the concentration of the element emitting it and independent of the state of chemical combination of that element.

Marie Curie noticed that certain ores showed greater activity than corresponded to their uranium content, and soon found that this was due to the presence of an unknown element, much more active than uranium. It was radium.

While separating radium salts from uranium ores the second radioactive element was discovered by Pierre and Marie Currie. They called it polonium, in honour of Poland, Marie Curie’s Motherland.

Notes on the text:

wrap –обертывать, завертывать.

emit – испускать, излучать.

correspond – соответствовать

affect smth. – влиять, воздействовать на ч.-л.

15. Read and retell the text using the underlined word-combinations:

The discovery of inert gases read like a romance. The first of inert gases discovered was argon. In 1894 Lord Rayleigh observed that density of atmospheric "nitrogen was greater than that of a chemical gas", and asked chemists to suggest a reason.

Sir Wiliam Ramsay asked if he might collaborate. They found that Cavendish in 1785 had noted that atmospheric nitrogen yielded an inert residue, after it had sparked with excess oxygen, that could not combine with oxygen. Was this a new gas? Rayleigh and Ramsay accordingly passed atmospheric nitrogen over magnesium to remove the nitrogen as solid magnesium nitride, Mg₃N₂, and introduced the residual gas into a Plucker tube and examined its spectrum. To their joy, although the characteristic lines of nitrogen were present, there were also new red and green lines suggesting the presence of a new element. As Rayleigh and Ramsay knew that this new gas was present in the atmosphere the story goes that in veiw of its remarkable inactivity they decided that they would call it argon, a Greek word meaning inert.

In 1868 the Danish astronomer Janssen examined the sun's corona spectroscopically for the first time in history. He detected that there was a prominent yellow line close to, but not identical with, the sodium lines which, however, did not correspond to any known element. By that time they had already stated that every element had its own characteristic spectrum and scientists could detect it. The chemists therefore suggested that this new line was due to an element present in the sun, but not present terrestrially. By that time scientists had already determined that alkali metals gave line spectra therefore they decided that the new element was a metal too. They suggested to call it helium, a Greek word meaning sun.

Notes to the text:

corona– солнечная корона

accordingly– соответственно, таким образом

in view of– ввиду

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