1)

Hydrogen (1H1), deuterium (1H2), singly ionised helium   (2He4)+   and doubly ionised lithium(3Li8)++ all have one electron around the nucleus. Consider an electron transition from n=2 to n=1 . If the wavelength s of emitted radiation are   λ1,λ2,λ3 and   λ4, respectively for four elements, then approximately which one of the following is correct?

 


A) 4λ1=2λ2=2λ3=λ4

B) λ1=2λ2=2λ3=λ4

C) λ1=λ2=4λ3=9λ4

D) λ1=2λ2=3λ3=4λ4

Answer:

Option C

Explanation:

For hydrogen atom, we get

 1λ=Rz2(112122)1λ1=R(1)2(34)

 1λ2=R(1)2(34)

          1λ3=R(2)2(34)

                    1λ4=R(3)2(34)

                       1λ1=14λ3=19λ4=1λ2