1,6,1,2 that should be the answer
Bohr model is valid only for hydrogen and hydrogen-like species, but quantum mechanical model can explain all elements....
the oxidation states of the elements before and after the reaction is;
Pb oxidation state changes from 0 to +2
SO₄²⁻ ion there's no change in the oxidation state during the reaction
Au oxidation state changes from +3 to 0
reduction reactions are when there's a decrease in the oxidation state of the species
oxidation reactions are when theres an increase in the oxidation state of the species
the element where there's a decrease in oxidation state is Au.
Therefore Au gets reduced.
answer is B) Au
A crystal<span> or </span>crystalline solid<span> is a </span>solid<span> material whose constituents (such as </span>atoms<span>, </span>molecules<span> or </span>ions<span>) are arranged in a highly ordered microscopic structure, forming a </span>crystal lattice<span> that extends in all directions.</span><span> In addition, macroscopic </span>single crystals<span> are usually identifiable by their geometrical shape, consisting of flat </span>faces<span> with specific, characteristic orientations. example of it are ice, rocks , organigenic crystals</span>