Question

The number of nodal plane in ${{p}_{x}}$ orbital is:
[A] One
[B] Two
[C] Three
[D] Zero

Answer 1

Hint: There are 3 p-orbitals that we know of namely ${{p}_{x}},{{p}_{y}}\text{ and }{{\text{p}}_{z}}$. The nodal plane is a plane at which the probability of funding any electrons is zero. To find the solution to this question, identify the azimuthal quantum number of the given orbital. The number of nodal planes will be equal to the azimuthal quantum number ‘l’.

Complete step by step answer:
To answer this question, firstly we have to understand what a nodal plane is.
A nodal plane is a region around the atomic nucleus where the probability of finding an electron is zero. A nodal plane basically passes through the nucleus.
Now, let us try to find the number of nodal planes in ${{p}_{x}}$ orbital.
We know that the p-orbitals are dumbbell shaped and there are three p-orbitals and are aligned along the perpendicular axes and are named ${{p}_{x}},{{p}_{y}}\text{ and }{{\text{p}}_{z}}$.
The ${{p}_{x}}$ orbitals lie along the x-axis and in the y-z plane.
Now as we know the number of nodal planes depends upon the azimuthal quantum number, l to find the number of nodal planes we have to find the azimuthal quantum number of p-orbital.
We know for s-orbital l is zero and that for p-orbital is 1.
Azimuthal quantum number of p-orbital = 1.
Therefore, the number of nodal planes in any p-orbital is 1. There are a total 3 p-orbitals and each has 1 nodal plane. So, we can write that the number of nodal planes in ${{p}_{x}}$ orbital is 1. The nodal plane for this orbital is along the y-z axis.
So, the correct answer is “Option A”.

Note: In a molecular orbital there are two types of nodes – angular node and radial node.
The number of angular node is equal to the azimuthal quantum number, l, and the number of radial nodes id equal to (n-l-1) where n is the principal quantum number
However, as we can see above, the number of nodal planes depends upon the shape of the orbital. For s-orbitals, there are zero nodal planes and for d-orbitals, the number of nodal planes is 2.