Which state of triply ionised Beryllium ( Be ⁺⁺⁺ ) has the same orbital radius as that of the ground state of hydrogen?

Step-by-step solution

Radius of n th-orbit in hydrogen like atom is given by r= n² h² 4 ² m k Z e² i.e., r n² Z For hydrogen, Z=1, n=1 in ground state n² Z = 1² 1 =1 For Beryllium ( Be ⁺⁺⁺ ), Z=4 orbital is same n² Z =1 n²=1 Z n²=4 n=2 Thus, the second level of triply ionised Be ⁺⁺⁺ has same radius as the ground state of hydrogen.