Question

The plots of radial distribution functions for various orbitals of hydrogen atom against r are given below: The correct plot for 3s orbital is : 

• A. A
• B. B
• C. C
• D. D

Hint:

The number of peaks in a radial distribution function is always equal to $n - l$. For 3s, there are $3 - 0 = 3$ peaks and $3 - 1 = 2$ nodes.

Answer 1

The Correct Option is C

Step 1: The number of radial nodes for any orbital is given by the formula: $\text{Radial Nodes} = n - l - 1$.
Step 2: For a 3s orbital, the principal quantum number $n = 3$ and the azimuthal quantum number $l = 0$.
Step 3: Substitute the values: $\text{Radial Nodes} = 3 - 0 - 1 = 2$.
Step 4: A radial distribution function plot ($4\pi r^2 \psi^2$ vs $r$) for a 3s orbital will touch the x-axis (zero probability) exactly at two points before reaching the final peak.