Which of the following species are expected to give the line spectrum similar to that of hydrogen atom?

Which of the following species are expected to give the line spectrum

1.	Which of the following species are expected to give the line spectrum similar to that of hydrogen atom?
Answer» He(g) `LI^(2+) (g)` `He^(+) (g)` D(g) Solution :SPECIES having SINGLE electron give LINE spectrum, similar to that of hydrogen atom.