regularities in the periodic system 

7. grade

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through history

Problem 10. The German chemist Julius Lothar von Meyer, independently of Mendeleev, grouped the chemical elements according to the increasing of their atomic mass and according to their valence. In 1864, he published his first table which contained the chemical symbols of only 28 of the then known chemical elements.

Meyer‘s table, 1864

Ред

Валентност

Разлика

 

ІV

ІІІ

ІІ

І

І

ІІ

в масите

І

 

 

 

 

Li

Be

~ 16

ІІ

C

N

O

F

Na

Mg

~ 16

ІІІ

Si

P

S

Cl

K

Ca

~ 45

ІV

 

As

Se

Br

Rb

Sr

~ 45

V

Sn

Sb

Te

I

Cs

Ba

~ 90

VІ

Pb

Bi

 

 

Tl

 

~ 90

 

а) Compare the contemporary periodic table with Meyer‘s table. Which groups of chemical elements were included in the table from 1864?  

b) Find out which element symbol has not been correctly placed in Meyer‘s table.

 

 

Some answers

 а) A groups, in the row – ІVА, VА, VІА, VІІА, ІА, ІІА; there are no symbols of chemical elements from group ІІІА with the exception of Tl which was given as an analogue to Cs.

 b)  Tl.

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