Why are elemental dopants for Silicon or Germanium usually chosen from group XIII or group XV?

Why zero group elements are inert ?

Group 13 elements show

Why Mg and Al does not belong to same group?

Why elements of Group 18 are less reactive or inert ?

Why are the elements of Group 18 known as noble gases ?

The elements of group 16 are called

Why elements of Group 18 are less reactive or inert?

._(90)Th is a member of III group . After losing alpha -particle it forms a new element belonging to : a) I group b) II group c) III group d) IV group