6
. The periodic law was accepted and widely used by chcmists. 7. It was
found that the atomic weights which had been accepted for some elements
were not accurate.
8
. After the paper on the periodic
table was presented,
it was soon published in Russian and in German. 9. Properties of chcmical
elements and compounds arc thoroughly studied in laboratories. 10. Some
elements were given new places in the table after the revision of their'
atomic weights. 11. The inversion o f the order in the periodic system has
now been rccognizcd as having little significance. 12. The periodic
law is
widely applied by chcmists. 13. Radon was discovered during the
investigation o f the properties o f radium and radioactive substanccs.
Ex. 11. Translate the scntcnccs into English.
I. Когда Менделеев разрабатывал периодическую систему, мно
гие элементы еще не были открыты. 2. Русское химическое обще
ство было основано в 1868 году. 3. Нулевая группа была добавлена к
периодическом таблице после открытия инертных газов. 4. Предска
зания Менделеева оправдались последующим открытием новых эле
ментов. 5. Гелий, неон, аргон, криптон и ксенон были открыты в
1894 году и в последующие годы.
6
. Всю свою жизнь Менделеев по
святил развитию науки. 7. Химические свойства указывали на нару
шение порядка в нескольких местах в таблице.
8
. Менделеев пред
сказал существование шесте элементов.
Ex. 12. Make up questions to the italicized parts of the scntcnccs.
1.
Mendeleyev proposed a periodic
table containing seventeen columns
(2). 2. The
periodic table was acccptcd
immediately after its proposal (2).
3. Most of the elements
occur in the periodic table in the order of increasing
atomic weight (
2
).
Ex. 13. Answer the following questions:
1. When did Mendeleyev present his periodic system? 2. Were there
noble gases in his periodic table? 3. Why did Mendeleyev revise his
table? 4. What elements arc there in Group “0”? 5. How arc elements
arranged in the system?
6
. Why arc there elements in the inverted
order
of atomic weights? 7. What discoveries verified Mendeleyev’s pre
dictions?
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