Question

The stable nucleus that has a radius half that of Fe⁵⁶ is:

Options

• Li⁷

• Na²¹

• S¹⁶

• Ca⁴⁰

Answer 1

Li⁷

^Explanation:

Nuclear radius = R = R₀A^1/3

It shows that R ∝ A^1/3

R³ ∝ A

Further A ∝ R³

Now, A₂/A₁ = (R₂R₁)³ = [(R₁/2)/R₁]³ = 1/8

Now, A₂ = A₁/8 = 56/8 = 7 

Hence, stable nucleus having radius half of Fe⁵⁶ is Li⁷.