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

Solution

Chemistry ma’am · 3 steps

Count the humps: a 3s orbital has two radial nodes, so its plot must show three peaks.

1. Radial nodes. The number of radial nodes is n - l - 1. For 3s, n = 3 and l = 0, so it has 3 - 0 - 1 = 2 radial nodes.
2. Nodes to peaks. At each radial node the curve drops to zero between two humps. So 2 nodes split the curve into 3 peaks, and the outermost peak is the tallest and farthest out.

   Plot	Peaks	Radial nodes	Matches
   (A)	1, near 0.5 Å	0	1s
   (B)	2	1	2s
   (C)	1, near 2 Å	0	2p
   (D)	3, tallest near 7 Å	2	3s

3. So. Only plot (D) has three peaks with two zeros between them, so it is the 3s orbital. That is option (d).

The idea to keep. For any radial distribution plot, find radial nodes with n - l - 1. The curve has one more peak than nodes, and higher n pushes the main peak farther out.

Answer from the NTA final answer key. Solution by PrepWiser.