Translate and memorize the following words. Unit III great chemists

UNIT III GREAT CHEMISTS

Complete the sentences. Choose the answer A, B, or C which you think fits best.

Fill in the gaps using the words below.

1. Newlands … his relation the law of octaves, by analogy with the seven intervals of the musical scale.

2. A long time was … for the recognition of the fact that the elements can be classified in the way now described by a periodic table.

3. In 1871 Mendeleyev and Meyer each proposed a table with eight columns, obtained by … each of the long periods into periods of seven elements.

4. Further experimental work … that Mendeleyev … were correct.

5. Mendeleyev made a … study of the relation between the atomic weights of the elements and their physical and chemical properties with special … to valence.

6. This … of order from that of atomic weight caused much … before the atomic numbers of elements were discovered, but has been recognized as having little ….

significance, require, revision, inversion, thorough, attention, splitting, verify, concern, term.

One of the most important modern chemical theories is the Periodic (… 1 …). It can simply be stated as follows: “The properties of the elements are a periodic function of the nuclear (…2...) of their atoms”.

In 1869 the great Russian scientist D.I. Mendeleyev came to the conclusion that by the (…3…) of the elements in order of (…4…) atomic weight the (…5…) and periodicity of properties of various valence groups of the elements were clearly seen.

There were several (…6…) spaces in Mendeleyev’s Periodic table. This allowed him to (…7…) the existence of six unknown elements (scandium, gallium, germanium, polonium, etc). His confidence in the new classification was clearly (…8…) in the predictions which he made of the chemical properties of these missing elements. And within fifteen years, gallium, scandium and germanium were discovered.

The periodic table has been modified hundreds of times. Many new discoveries, isotopes, rare gases, atomic numbers, and electron configurations have (…9…) the idea of the periodicity of the properties of the elements.

	A) low	B) law	C) lay
	A) changes	B) numbers	C) charges
	A) arrangement	B) assortment	C) selection
	A) decreasing	B) increasing	C) rising
	A) resemblance	B) simplicity	C) similarity
	A) missing	B) free	C) vacant
	A) predict	B) add	C) guess
	A) explained	B) expressed	C) conducted
	A) strengthed	B) strengthened	C) strong

Grammar: The Absolute Participle Construction

Text: M. V. Lomonosov

contribute	corpuscular	assemble
devote to	kinetic	pigment
apply	particular	shade
refract	conclude	tint
distinguish	manufacture	cast
precipitate	polish	fusion
secure	melt	furnace

2. Define the parts of speech and translate these words:

apply – application; conclude – include – exclude – conclusion – exclusion; precipitate - precipitation - precipitating; consider - considerable; refract – refractory – refraction; melt – remelted – melting - remelting; particular – particularly.

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