Atoms · Question 19

Assuming the validity of Bohr's atomic model for hydrogen-like ions the radius of Li++ ion in its ground state is given by 1Xa0, where X = (Where a0 is the first Bohr's radius.)

1. 2
2. 9
3. 1
4. 3

Answer

(4) 3

Solution

Bohr radius for a hydrogen-like ion: rn = a0 n2Z

Li++: Z = 3, ground state n = 1

r1 = a03 = 1Xa0

X = 3

Answer: (4)