Why Zn, Cd and Hg are not transition elements?

Summary

This video explains why zinc, cadmium, and mercury, despite belonging to the d-block of the periodic table, are not considered transition elements. It outlines the criteria for transition elements, which must have an incomplete d-subshell either in their ground state or most common oxidation state. The video compares copper and zinc, explaining how copper qualifies as a transition element while zinc does not. It also highlights that cadmium and mercury follow similar rules and do not exhibit typical transition metal properties. The discussion concludes with a brief introduction to the characteristic properties of transition elements, to be explored in future content.

Takeaways

• 😀 Zinc, cadmium, and mercury are located in the d-block of the periodic table, but they are not considered transition elements.
• 😀 A transition element must have an incomplete d-subshell either in its ground state or most common oxidation state.
• 😀 Zinc, cadmium, and mercury have completely filled d-subshells in both their ground state and most common oxidation states, which disqualifies them as transition elements.
• 😀 Zinc's electronic configuration is 4s² 3d¹⁰, and Zn²⁺ has the same 3d¹⁰ configuration, meaning its d-orbitals are completely filled.
• 😀 Cadmium and mercury also have completely filled d-orbitals in their ground states and common oxidation states, preventing them from being classified as transition elements.
• 😀 Copper, despite having a 3d¹⁰ configuration in its ground state (4s¹ 3d¹⁰), is considered a transition element because its Cu²⁺ ion has a 3d⁹ configuration, which is partially filled.
• 😀 The key criterion for a transition element is the presence of a partially filled d-subshell in either the ground state or common oxidation states.
• 😀 Zinc, cadmium, and mercury do not exhibit partially filled d-orbitals, unlike other transition elements.
• 😀 The definition of transition elements involves having a d-orbital that is not fully filled in common oxidation states, as opposed to elements like zinc, cadmium, and mercury.
• 😀 Transition elements are characterized by their ability to form multiple oxidation states and their use in various chemical reactions due to the partially filled d-orbitals.

Q & A

What is the main criterion for an element to be considered a transition metal?

An element must have an incomplete d-subshell either in its ground state or in its most common oxidation state to be considered a transition metal.

Why are zinc, cadmium, and mercury not considered transition metals?

Zinc, cadmium, and mercury have completely filled d-subshells in both their ground state and common oxidation states, so they do not meet the criteria of having an incomplete d-subshell.

What is the difference between a d-block element and a transition metal?

While all transition metals are d-block elements, not all d-block elements are transition metals. A transition metal must have an incomplete d-subshell in its ground state or common oxidation state.

Which groups of the periodic table correspond to the d-block?

The d-block corresponds to groups 3 to 12 of the periodic table.

What is the electron configuration of zinc, and why does it prevent zinc from being a transition metal?

The electron configuration of zinc is 4s² 3d¹⁰. Since zinc has a completely filled d-subshell (3d¹⁰), it does not qualify as a transition metal.

What is the electron configuration of copper, and why is copper considered a transition metal despite having a filled d-subshell?

Copper has an electron configuration of 4s¹ 3d¹⁰. Although copper's ground state has a filled d-subshell, its +1 oxidation state (Cu⁺) has an incomplete d-subshell (3d¹⁰), fulfilling the transition metal criteria.

Why are the elements of group 12 like zinc, cadmium, and mercury not known for typical transition metal properties?

Since group 12 elements have completely filled d-subshells in their ground states and common oxidation states, they do not exhibit the typical properties of transition metals, such as variable oxidation states and complex ion formation.

Can an element in the d-block be a transition metal if it has a completely filled d-subshell in its ground state?

No, an element in the d-block cannot be a transition metal if it has a completely filled d-subshell in its ground state, as it does not meet the requirement for an incomplete d-subshell.

What happens to the electron configuration of copper when it forms a +2 oxidation state?

In the +2 oxidation state, copper's electron configuration becomes 3d⁹, as two electrons are lost from the 4s orbital, making it a transition metal in this state.

What defines a transition element in terms of its most common oxidation state?

A transition element must have an incomplete d-subshell either in its ground state or in its most common oxidation state, which allows it to display the characteristic properties of transition metals.