Classification ...

The successive ionisation energy values for an element 'X' are given below:

(i)     1^st ionisation energy = 410 kJ mol^-1
(ii)    2^nd ionisation energy = 820 kJ mol^-1
(iii)   3^rd ionisation energy = 1100 kJ mol^-1
(iv)   4^th ionisation energy = 1500 kJ mol^-1
(v)    5^th ionisation energy = 3200 kJ mol^-1

Find out the number of valence electrons for an atom of 'X'.

Correct option to complete the following statement  is :
"Mendeleeve's classification of element is based upon similarites in properties of different elements with increasing order of their atomic weights .
In cases where  dissimarites in properties of an element appeared he placed the elements with similar ......... together".

In the modern periodic table

The existence of which of the following became the reason for the failure of Mendeleev's periodic law?

Mendeleev 'Periodic Law' states that

Choose one of the following in the order of increasing radii:

Which of the following statements is correct?

Dmitri Mendeleev (1834-1907) and the German chemist, Lothar Meyer (1830-1895) proposed arranging elements in

The elements of the same group of the periodic table have the same

Mendeleev arranged the elements on the basis of their