Alkali metals lose electrons from which orbitals?

$DDT$ residues are rapidly passed through food chains causing biomagnification. What is the reason for this?

$(\sqrt{3}+i)^7+(\sqrt{3}-i)^7$ is equal to (in $\sqrt{3}$)

$A$ piece of iron is heated in a flame. It first becomes dull red, then becomes reddish yellow, and finally turns to white hot. The correct explanation for the above observation is possible by using:

Which of the following compounds is formed by the addition of a mineral acid to an aqueous solution of borax?

For a sample of a perfect gas,when its pressure is changed isothermally from $p_i$ to $p_f$,the entropy change is given by: