Question

Which pair of similar elements were placed in different group in Mendeleev's
periodic table?
(1) Li and Be
(2) Si and C
(3) Ca and Sr
(4) Au and Pt​

Answer 1

Answer:

Li and Be

Explanation:

A diagonal relationship exists between certain pairs of diagonally adjacent elements in the second and third periods. These are the first 20 elements in the periodic table.  

For example, pairs lithium (Li) and magnesium (Mg), beryllium (Be) and aluminium (Al), boron (B) and silicon (Si), etc are exhibiting similar properties. Boron and Silicon are both semiconductors.  

Thus Magnesium and Lithium have similar properties.

Answer 2

Explanation:

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