A vacant полагать, считать property вес, масса to consider столбик probably пустой dependence располагать weight зависимость serve ряд column служить to arrange свойство b

Read the sentence pairs. Choose which word or phrase best fits each blank

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periodic table

3. Put the key words into the sentences of the text.

2. Read the sentence pairs. Choose which word or phrase best fits each blank.

1. electron shell/block

A) An atom may have more than one ______________ .
B) Similar elements tend to occupy the same ______________.

2. atomic radius/ periodic table

A) The _______________ lists important information about the elements.
B) An atom with more electron shells also has a larger _____________.

3. electron affinity/electron configuration

A) Scientists have many ways of modeling an atom’s _______________.
B) ___________________ made the newly formed become negatively charged.

4. transmission metals/non-metals

A) The _______________ tend to be gaseous at room temperature.
B) The majority of the elements are considered ____________________.

5. inert gases/metalloids

A) The __________ have full valence shells and are not reactive.
B) Most _____________________ conduct electricity in their liquid form.

3. Put the key words into the sentences of the text.
Discovered, periodic, in, column, elements, right, atomic, properties, future, vacant

Mendeleyev's Periodic Law

Mendeleyev's 1) ___________Law The Periodic Law 2)__________ by D. I. Mendeleyev 3)____________1869. Mendeleyev arranged the elements in tabular form in such a way as to bring their correspondences quite clearly. The 4) _______________are divided into eight groups, each of which is entered in a separate 5)_________________. They are also divided into 10 «series» each of which is entered upon one horizontal line. The 6)_____________ weights increase across the table from left to the 7) _________. D. I. Mendeleyev was the first to discover the law of dependence of the 8) ___________ of the elements upon their atomic weights. The elements in any one column are similar to one another in many ways, the resemblance being very striking. Mendeleyev found it impossible to construct his table without leaving many of the spaces in it 9)________. He considered these vacancies to correspond the elements which were not then known, but which would probably be discovered in the 10) _________. Today the Periodic Law is studied by millions of secondary schoolchildren and by the students at higher establishments of natural sciences and engineering. It is studied by philosophers, historians and teachers. The Periodic Law serves as a platform for thousands of researches.

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