Can `NCI_(5)` be prepared by direct union of the elements ? Why ? or Why not? 

Which among the following compound cannot be prepared by direct union of elements ?

Is Lanthanum a real lanthanide element ? Why? or Why not?

Which of the following can be prepared by the direct union of elements ?

ZnI_2 , can be prepared by the direct combination of elements. A chemist determines from the amounts of elements that 0.0654 mol ZnI_2 can be formed.

Why are the elements of zero group inert?

Why do some elements be monoatomic?

Which of the following compounds cannot be prepared by direct reaction between the constituent elements

Why are the atoms of different elements different?