Two single-electron species are considered: hydrogen ( ) and singly-ionised helium ( , ).

CHEMISTRY · Multi-part · CBSE · Chemistry · Structure of Atom · Structure of Atom

Problem

Two single-electron species are considered: hydrogen (

Z=1

) and singly-ionised helium (

\text{He}^+

Z=2

). (a) Derive an algebraic expression for the ratio

\dfrac{v_{n\,(\text{He}^+)}}{v_{n\,(\text{H})}}

of the electron speeds in their respective

n^{\text{th}}

orbits. (b) Hence evaluate the ratio for

n=2

. (c) State which electron moves faster in that orbit and give a physical explanation based on your result.