[Khyati]

1)The p type semiconductors is obtained when Si is doped with (a)Al (b)Ga  [ p type semiconductors are made when elements are doped with the group 13 elements, here in options both are from 13 group & answer given  is Ga, why cant (a) be the correct answer too since it also belongs to 13Th group]

2)Schottky defect is due to

a)missing of electron

b)missing of atom

I have read it ts due to missing of atoms, but the option (a) is given correct.

3)Which of the following crystals has lagrest lattice energy & why?I really don't have idea about this question
 
(a)KCl   (b)RbI   (c)MgO  (d) NaF