Difference Between First Second and Third Transition Series

The key difference between first second and third transition series is that the outermost d orbital of first transition series elements is 3d while the outermost d orbital second transition series is 4d and the outermost d orbital in third transition series is 5d.

A transition metal is a chemical element that has a partially filled d orbital. In the periodic table of elements, there are three series of transition elements; we name them as first, second and third transition series. These are chemical elements of three different periods in the periodic table. Therefore, they contain different outermost orbitals.

CONTENTS

1. Overview and Key Difference
2. What is the First Transition Series
3. What is the Second Transition Series
4. What is the Third Transition Series
5. Side by Side Comparison – First vs Second vs Third Transition Series in Tabular Form
6. Summary

What is the First Transition Series?

First transition series is the list of chemical elements ranging from Scandium to Copper. We can also describe them as first-row transition metals because these are metals included in the first period of the d block, which contains the transition metals. Therefore, when considering the electron configuration of these elements, all these elements have 3d and 4s electrons. This means the outermost d orbitals of these elements are 3d orbitals. Furthermore, the elements of this series contain a complete Argon electron configuration with 3d and 4s electrons.

Chemical Elements in the First Transition Series

The list of the chemical elements in this series are as follows:

• Scandium
• Titanium
• Vanadium
• Chromium
• Manganese
• Iron
• Cobalt
• Nickel
• Copper

What is the Second Transition Series?

Second transition series is the list of chemical elements ranging from Yttrium to silver. We can name them as second-row transition metals as well because they are in the second period of the d block and they are metals. The electron configurations of these elements have 4d and 5s orbitals; hence, the outermost d orbitals are 4d orbitals. Furthermore, the elements of this series contain a complete Krypton electron configuration with 4d and 5s electrons. The members of this list are as follows:

Chemical Elements in the Second Transition Series

• Yttrium
• Zirconium
• Niobium
• Molybdenum
• Technetium
• Ruthenium
• Rhodium
• Palladium
• Silver

What is the Third Transition Series?

Third transition series is the list of chemical elements ranging from Hafnium to gold, plus Lanthanum. These are in the third period of d block, and it also contains the first member of the lanthanide series (Lanthanum) as well because the third transition series elements and Lanthanum have 5d and 6s electron orbitals in their electron configuration. Furthermore, the elements of this series contain a complete Xenon electron configuration with 5d and 6s electrons.

Chemical Elements in the Third Transition Series

• Lanthanum
• Hafnium
• Tantalum
• Tungsten
• Rhenium
• Osmium
• Indium
• Platinum
• Gold

What is the Difference Between First Second and Third Transition Series?

In the periodic table of elements, there are three series of transition elements we name as first, second and third transition series. The key difference between first second and third transition series is that the outermost d orbital of first transition series elements is 3d while the outermost d orbital of second transition series is 4d and the outermost d orbital of third transition series is 5d.

Moreover, the first transition series is the list of chemical elements ranging from Scandium to Copper. The second transition series is the list of chemical elements ranging from Yttrium to silver, while the third transition series is the list of chemical elements ranging from Hafnium to gold, plus Lanthanum. Among these three series, second and third transition series have closely related properties, which differs considerably from the properties of the first transition series.

Furthermore, the elements of the first transition series contain a complete Argon electron configuration with 3d and 4s electrons. However, the second transition series contains a complete Krypton electron configuration with 4d and 5s electrons. Meanwhile, the elements of the third transition series contains a complete Xenon electron configuration with 5d and 6s electrons. So, this is also a significant difference between first second and third transition series.

Summary – First vs Second vs Third Transition Series

In the periodic table of elements, there are three series of transition elements; we name them as first, second and third transition series. The key difference between first second and third transition series is that the outermost d orbital of first transition series elements is 3d while the outermost d orbital of second transition series is 4d and the outermost d orbital of third transition series is 5d.

Reference:

1. “23.1: General Properties of Transition Metals.” Chemistry LibreTexts, Libretexts, 18 Sept. 2019, Available here.
2. “Third Transition Series (or) 5d-Series.” Simply Science, Available here.

Image Courtesy:

1. “Transition Metals Ionization Energies” By Oncandor – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Simple Periodic Table Chart-en” By Offnfopt – Own work (Public Domain) via Commons Wikimedia