Transition Elements - Definition, Properties, FAQs

What is transition?

Transition elements meaning or Transition elements means: Elements of the periodic table are classified in four categories 1. Main group element 2.transition metals 3.lantanides 4. Actinides, in the other words we can say that the periodic table has 4 blocks namely as s, p, d, and f out of these the d block elements are basically known as the transition metals, transition elements are named transition because their properties lie between s and p block elements of the periodic table.

If we go through the orbital theory then these metals can be defined as the elements that have half-filled d orbitals, in the periodic table d-block elements from the groups 3–12 are transition elements, and the f-block elements, are called inner transition elements definition i.e. the lanthanides and actinides, also possess partially occupied d orbital before the f orbitals. In the copper family i.e. Group 11 the d orbital is completely filled ;that is why , group 12 elements are technically not transition elements. Sometimes group 12 elements are considered as the transition metal because of its equivalency with some properties of transition metals.

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Properties of Transition Elements

Physical Properties of Transition Elements;

They conduct heat and electricity very efficiently.

• They can be bent to any shape and also hammered very easily.

• They have high melting points (but mercury may be a liquid at room temperature).

• They are usually very tough.

• These metals also have high densities.

Chemical Properties of Transition Elements

The chemical properties of transition metals are as follows

• like sodium metal transition metals are less reactive.

• Transition metals forms ions with color and also of different charges’

• few of them like silver and gold are unreactive

• They can also be used as a catalyst in various types of chemical reactions

There are some other properties of transition elements like atomic radii, ionization energy, electronic general electronic configuration of transition elements etc. let just discus about them

Metallic Radius and Densities Transition Elements

The density of the d block elements i.e. the transition elements is higher than the s-block and density increases gradually from scandium to copper, this happens because the metallic radii of the elements decrease irregularly and relative increase in the mass.The below graph shows the variation of radii and density of the transition elements.

Melting and Boiling of Transition Elements;

If we compare the melting point and boiling point of the transition elements then we can say that these are generally higher than the elements of the main group. It can be better understood from the following figure.

Ionization Energy of Transition Elements

When we go across the metal series from scandium there will be small change in the 1st ionization energy and the 2nd ionization energy, it happens because electrons build up occurs immediately in d-sub-shells due to which the 4s electrons are shields in the nucleus and which minimize the effective nuclear charge from one element to other . There is a rapid increase in 3rd and 4th ionization energy,because of unpaired electrons of 5d subshell, in singly occupied orbitals.and due to this the inter electron repulsion occurs When the 6th and the further electrons enter in the shell due to which it has to share its orbital which is already occupied, and there is a less requirement of energy to remove electron. That's why the curve of 3rd ionization energy is identical in shape for the last five elements..

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Electronic General Electronic Configuration of Transition Elements of Transition Element

As we have seen above in the definition that the transition metals are placed in the d block of the periodic table or in the other words we can say that the d block elements are called transition this is so because when we proceed across the row of each column then we found an additional d orbital. The electronic electronic configuration of transition elements for the first row of lower energy for transition elements list is shown below.

Generally the electronic general electronic configuration of transition elements for first series transition metals i.e. from the group 3 to 12 will be written as 3dⁿ 4s². There are some exceptions also for example electron general electronic configuration of transition elements for Cr is =(3d⁵ 4s¹) and for Cu= (3d¹⁰ 4s¹).

Because the energy of 3d and 4s orbitals are quite similar, and the energy of 3d orbital decreases when going through the row.

In the general electronic configuration of transition elements in 3d orbital if there are more no. of electron then there will be less amount of energy for both in chromium and copper also Because the difference in pairing energy and orbital energy is approximately the same. The general electronic configuration of transition elements 3d⁵ 4s¹ has lower energy because for the d subshell it has a maximum number of unpaired electrons. 3d orbital energy at copper has dropped that’s why 3d orbitals are of lower energy than 4s orbitals. Hence the 3d¹⁰ 4s¹ general electronic configuration of transition elements is of lower energy because the 3d orbital has more number of electrons.

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NCERT Chemistry Notes:

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