The history of the periodic table  

UNIT II

THE HISTORY OF THE PERIODIC TABLE  

Section I

Many innovators have developed periodic tables which display chemical elements differently from the well-known Mendeleev's periodic table. Several have been devised purely for didactic reasons, as not all correlations between the chemical elements are effectively captured by the standard periodic table. Nevertheless Mendeleev'speriodic table is still considered one of the most important tools in chemistry.

WARMING-UP

What do you know about the periodic table of Mendeleev?

Do you consider it helpful for chemists?

Do you know any other variations of the periodic table?

What important information on newly discovered elements can you give?

Complete the chart and share your ideas with your fellow students.

 

THE PERIODIC TABLE

groups

elements

properties

D.I. Mendeleev

 

 

TEXT A

Memorize the meaning of the following words and word combinations.

accept, add, application, cause, close, compound, concern, contain, entirely, increase, inverse, investigation, lead, mixture, noble, occur, propose, recognize, relation, resemble, respectively, revise, search, significance, striking, success, thorough, vacant, value, weight

Practise your pronunciation.

Valence, column, helium, neon, argon, krypton, xenon, cobalt, nickel, tellurium, iodine, protactinium, thorium, scandium, gallium, germanium, isotope.

 

Make pairs of the words and word combinations in column A and those in column B and make up the sentences with them.

	A		B
1.	striking	a)	table
2.	vacant	b)	values
3.	noble	c)	application
4.	atomic	d)	elements
5.	radioactive	e)	significance
6.	periodic	f)	weight
7.	revised	g)	substances
8.	pairs of	h)	place
9.	little	i)	properties
10.	predicted	j)	gases

Read and translate the text.

Give the English equivalents for the following words and word combinations.

Наиболее важный шаг, периодическая таблица, отношение, атомный вес, между, особое внимание, содержать, инертный газ, пересмотреть таблицу, ряд элементов, нулевая группа, добавить к чему-л., успех, большинство элементов, в обратном порядке, атомный номер, смесь изотопов, состоять из, главным образом, большое значение, применение, свободные места в таблице, таким образом, вскоре, химическое соединение, в воздухе, привести к.

 

Complete the sentences using the appropriate derivatives of the words in capitals.

1. Chemists accepted the periodic law immediately after its … /PROPOSE/.

2. Mendeleev made a very striking … of the periodic law /APPLY/.

3. The periodic law clearly indicated the … of neon, krypton, xenon and radon /EXIST/.

4. This … of the order in the periodic system caused much concern before the discovery of the atomic numbers of the elements /INVERSE/.

5. They discovered radon during the … of the properties of radium and other radioactive substances /INVESTIGATE/.

 

7. Translate the following sentences paying attention to the different meanings of the words " that " and " those ".

 

1. Put your bag on that table. 2. Mendeleev found that the atomic weights were correlated with the properties of corresponding elements. 3. The atomic weight of potassium is 39.098 and that of argon is 39.948. 4. The inversion of the order in the periodic system from that of atomic weight caused much concern. 5. The properties of the elements and those of their compounds are close to those predicted by Mendeleev. 6. That difficulty exists no more. 7. The properties of those compounds are different. 8. Elements from Group I differ from those of Group II.

 

Put questions of different types to the following sentences.

 

1. Mendeleev proposed a periodic table containing seventeen columns. 2. Chemists added the "zero" group to the periodic table after the discovery of helium, neon, argon, krypton and xenon by Lord Rayleigh and Sir William Ramsay. 3. Most of the elements occur in the periodic table in the order of increasing atomic weights. 4. Mendeleev made a very striking application of the periodic law. 5. He predicted the existence of six elements which scientists discovered later.

 

Section II

TEXT B

Notes on the text:

array – массив, множество, таблица; coincide – совпадать; signify – означать; level – уровень; traverse – перемещаться; infer – делатьвывод, заключать; behave in a similar fashion – вестисебяподобнымобразом; familiar with – знакомыйс; determine a significant amount – определитьзначительноеколичество

1. Skim the text and entitle its paragraphs.

 

Answer the questions.

 

1. Why is the periodic table the most important chemistry reference?

2. How are elements arranged in the table?

3. What does the period number of an element signify?

4. How can one use the data in the periodic table?

5. What do chemists call a "group" of elements?

 

UNIT II

THE HISTORY OF THE PERIODIC TABLE  

Section I

Many innovators have developed periodic tables which display chemical elements differently from the well-known Mendeleev's periodic table. Several have been devised purely for didactic reasons, as not all correlations between the chemical elements are effectively captured by the standard periodic table. Nevertheless Mendeleev'speriodic table is still considered one of the most important tools in chemistry.

WARMING-UP