Question

how is the problem regarding the position of cobalt and nickel in Mendeleev's periodic table resolved in modern periodic table?

Answer 1

Answer: Mendeleev's Periodic Table was based on the law that the properties of elements are the periodic function of their atomic masses. So, cobalt with atomic mass 58.93 should be placed after nickel with atomic mass 58.71

Answer 2

Answer:

(i) Gold and Platinum occur in free state.

(ii) They are noble metals, hence they are least reactive.

(iii) They are not affected by air, water and other

natural factors.

(iv) Hence, pure gold and platinum always glitter.

Explanation: