Question

Number of short periods in Mendeleev table is :
(A) 2
(B) 3
(C) 4
(D) 1

Answer 1

Hint : Firstly we should be clear what exactly a period is, it is the arrangement of the periodic table which has the elements with the same amount of shells in their natural state or neutral state. Now in the Mendeleev Periodic Table atomic weight is considered the criteria and the elements were also used accordingly. In the ultimate form of the table there are 7 rows and 8 columns in the table .

Complete Step By Step Answer:
Firstly we need to know what exactly a period is :
Any period in the modern periodic table refers to a row of chemical elements with the same ultimate shell. That means that all elements which are in the row must have the same number of electron shells.
The Period number 1, 2 and 3 contain 2, 8 and 8 elements respectively. Other periods contain more than 8 elements in their period. This is because the first three periods are called short periods. Therefore there are a total of 3 short periods in the Mendeleev periodic table.
It uses the atomic weight as a criteria to organize the elements. The information determinable is considered as fair precision in that time as it was the basic criterion. Now, this atomic weight has also worked well enough to allow Mendeleev to accurately predict the properties of missing elements.
Now as per the mendeleev form of periodic table it is observed that there are a total of the 7 periods in the long form of table in which there are a total 3 short periods in the Mendeleev periodic table.
Therefore the correct option is option B.

Note :
Russian chemistry professor Dmitri Mendeleev and German chemist Julius Lothar Meyer independently published their periodic tables 1869 and 1870 , respectively. Mendeleev's table, dated 1 March, 1869 was his first published version. That of Meyer was an expanded version of his (Meyer's) table of 1864.