JEE Main 2022 · 30 June · morning · Single correct · +4 / −1

The number of radial nodes and total number of nodes in 4p orbital respectively are :

  1. (a) 2 and 3
  2. (b) 2 and 2
  3. (c) 3 and 4
  4. (d) 4 and 4
Answer and solution

Answer (a) 2 and 3

Solution

Chemistry ma’am · 4 steps

Read off n and l from 4p first; every node count follows from those two numbers.

  1. Quantum numbers. For a 4p orbital, n = 4. A p orbital has l = 1.
  2. Two kinds of node. Radial nodes are spheres where the electron density is zero, and there are n - l - 1 of them. Angular nodes are planes or cones, and there are l of them.

    total nodes = (n - l - 1) + l = n - 1

  3. Put in numbers. Radial nodes = 4 - 1 - 1 = 2. Angular nodes = 1. Total nodes = 2 + 1 = 3, which matches n - 1 = 3.
  4. So. The 4p orbital has 2 radial nodes and 3 nodes in total, which is option (a).

The idea to keep. Radial nodes are n - l - 1, angular nodes are l, and together they always make n - 1. Find n and l first, then the rest is subtraction.

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

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Asked about 170 times in JEE Main since 2020. This question is from 2022.