Difference Between Px Py and Pz Orbitals

The key difference between Px Py and Pz orbitals is that the Px orbital has two lobes oriented along the x-axis and the Py orbital has two lobes oriented along the y-axis whereas, the Pz orbital has two lobes oriented along the z-axis. Therefore, the difference between Px Py and Pz orbitals arises from their orientation in space.

An atomic orbital is a region around an atomic nucleus, which has the highest probability of finding an electron. The orbitals of an atom can be either s orbital, p orbital, d orbital, or f orbital. Furthermore, there are three p orbitals; they are Px, Py and Pz orbitals.

CONTENTS

1. Overview and Key Difference
2. What is a Px Orbital
3. What is a Py Orbital
4. What is a Pz Orbital
5. Similarities Between Px Py and Pz Orbitals
6. Side by Side Comparison – Px vs Py vs Pz Orbitals in Tabular Form
7. Summary

What is a Px Orbital?

Px orbital is one of three p orbitals and orients along the x-axis. Moreover, this orbital has two lobes and has a dumbbell shape. Quantum numbers are a set of numbers that help to name atomic orbitals. This system gives a particular atomic orbital a unique name.

Quantum Numbers:

• Principle quantum number (n) describes the electron shell. Ex: n = 1, 2, 3…
• Azimuthal quantum number or the angular momentum quantum number (l) explains the subshells. Ex: l = 0, 1, 2…
• Magnetic quantum number (m) indicates the unique quantum state of an electron. Ex: m = …-2, -1, 0, +1, +2…
• Spin quantum number (s) describes the spin of an electron. Ex: s = ±

When considering the Px orbital, the quantum notation is as follows.

• When n=1, there are no P orbitals.
• When n > 2, and l = 1, there are p orbitals. Then, Px is either m = +1 or m = -1.
• With the increasing n values, the size of the outer lobe of the Px orbital increases gradually while the inner lobe size decrease.

What is a Py Orbital?

Py orbital is one of three p orbitals oriented along the y-axis. This orbital has two lobes. The quantum notation of Py orbital is as follows.

• When n=1, there are no P orbitals.
• When n > 2, and l = 1, there are p orbitals. Then, Py is either m = +1 or m = -1.
• With the increasing n values, the size of the outer lobe of the Py orbital increases gradually while the inner lobe size decrease.

What is a Pz Orbital?

Pz orbital is one of three p orbitals oriented along the z-axis. This orbital has two lobes and has a dumbbell shape. The quantum notation of Py orbital is as follows:

• When n=1, there are no P orbitals.
• When n > 2, and l = 1, there are p orbitals. Then, Pz is either m = 0.
• With the increasing n values, the size of the outer lobe of the Pz orbital increases gradually while the inner lobe size decrease.

What are the Similarities Between Px Py and Pz Orbitals?

• Px Py and Pz Orbitals have a similar shape (dumbbell shape).
• All three P orbitals have a similar size.
• The sizes of these orbitals change with the increase of n value.
• All three orbitals contain two lobes along the same orientation of axis.

What is the Difference Between Px Py and Pz Orbitals?

Summary – Px Py vs Pz Orbitals

There are three p atomic orbitals in an atom. The names Px, Py and Pz, indicate the orientation of the orbital in space. The key difference between Px Py and Pz orbitals is that  Px orbital has two lobes oriented along the x-axis and Py orbital has two lobes oriented along the y-axis whereas Pz orbital has two lobes oriented along the z-axis.

Reference:

1. “Atomic Orbital.” Wikipedia, Wikimedia Foundation, 24 Apr. 2018, Available here.
2. Libretexts. “Atomic Orbitals.” Chemistry LibreTexts, Libretexts, 7 Feb. 2018, Available here.
3. Agray, Santosh. “Shapes of Orbitals.” Chemistry Desk, Available here.

Image Courtesy:

1.”Px py pz orbitals” By CK-12 Foundation – File:High School Chemistry.pdf, page 268 (CC BY-SA 3.0) via Commons Wikimedia