Question

what are the indefinite positions of hydrogen element in mendeleev's periodic table?

Answer 1

Explanation:

Similarities to Metals

Hydrogen shares many similarities with alkali metals, i.e. elements in group I-A. This is one of the factors that dictates the position of hydrogen in the table. Let us take a look at the similarities

Electronic Configuration: Like all the elements of the group, Hydrogen also has one electron in its last shell, the valence shell. Let us take a look at the composition of valence shells of a few of these alkali metals.

H (z=1) : K1

Li (z=3) : K2, L1

Na (z=11) : K2, L8, M1

Noble Gas Configuration: Like alkali metals, it needs to lose one electron in its valence shell to achieve stable configuration as that of the next noble gas, which in this case is helium. It hence forms the H+ ion.

Good Reducing Agent: Hydrogen is a strong reducing agent like all the other alkali metals.

Fe2O3 + 4 H2 → 3Fe + 4H2O

B2O3 + 6 K → 2B + 3 K2O

Forms Halides: Also just like alkali metals, hydrogen combines with electronegative elements to form halides

2Na + Cl2 → 2NaCl

H2 + Cl2 → 2HCl

Answer 2

Answer:

This paper addresses the conceptual as well as social origins of Mendeleev’s discovery of the periodic law and its reception by the chemical community by taking account of three factors: Mendeleev’s early research and its relevance to the discovery; his concepts of chemistry, especially that of the chemical elements; and the social context of the discovery and the reception in the chemical community. Mendeleev's clear distinction between abstract elements and simple bodies was a departure from Lavoisier’s famous definition of elements as an endpoint of analysis and originated from his research in indefinite compounds. As a comparison, the paper also analyzes Lothar Meyer’s approach to the classification of the elements. Mendeleev’s new concept of chemical elements and the existence of an audience in the form of the newly established Russian Chemical Society, and his ``German connection'', helped Mendeleev in his discovery and its reception.