The radius of the smallest electron orbit in hydrogen-like ion is (0.51 10⁻¹⁰ / 4 ) m , then it is

Step-by-step solution

For hydrogen like atom, the radius of n th orbit Here, aligned & r_n^z= n^2 Z a₀ & a₀=0.51 10⁻¹⁰ ~m & r_n^Z= 0.51 10⁻¹⁰ 4 ~m aligned In the ground state, n=1 aligned & & 0.51 10⁻¹⁰ 4 & = 1^2 Z 0.51 10⁻¹⁰ & & Z & =4 aligned So, the atom is triply ionised beryllium ( Be ³⁺ ) .