d-Block Elements (Transition Elements)
Study the position, general characteristics, and electronic configurations of d-block elements.
What is d-Block Elements (Transition Elements)?
Elements in which the last electron enters any of the four d-orbitals of the penultimate shell.
Key points
- Identify d-block elements in the periodic table.
- Write the general electronic configuration of d-block elements and explain exceptions.
- Describe the characteristic physical and chemical properties of d-block elements.
- Explain the reasons for variable oxidation states, formation of coloured compounds, catalytic activity, and alloy formation.
Common exam trap
Confusing d-block elements with transition elements (Zn, Cd, Hg exceptions).
Definitions
- Term
d-Block Elements
- Meaning
Elements in which the last electron enters any of the four d-orbitals of the penultimate shell.
- Term
Transition Elements
- Meaning
Elements that have incomplete d-orbitals in their elementary state or in one of their common oxidation states.
- Term
Variable Oxidation States
- Meaning
The ability of an element to exhibit more than one oxidation state, arising from the participation of electrons from both the outermost s-subshell and the inner (n-1)d subshell.
- Term
Paramagnetism
- Meaning
A property exhibited by substances that are weakly attracted by an external magnetic field, due to the presence of unpaired electrons.
- Term
Alloy
- Meaning
A mixture composed of two or more elements, at least one of which is a metal, typically produced by melting and mixing the constituent elements.
Learning objectives
Identify d-block elements in the periodic table.
Write the general electronic configuration of d-block elements and explain exceptions.
Describe the characteristic physical and chemical properties of d-block elements.
Explain the reasons for variable oxidation states, formation of coloured compounds, catalytic activity, and alloy formation.
Differentiate between d-block and f-block elements.
Understand the magnetic properties of d-block elements.
Prerequisites
Atomic Structure
Electronic Configuration
Periodic Classification of Elements
Chemical Bonding
Common mistakes
Confusing d-block elements with transition elements (Zn, Cd, Hg exceptions).
Incorrectly applying the general electronic configuration without considering exceptions.
Misunderstanding the reasons for variable oxidation states (involvement of both ns and (n-1)d electrons).
Forgetting that lanthanoids and actinoids are f-block elements, not d-block.
Overlooking the role of unpaired electrons in colour and magnetism.
Assuming all d-block elements are equally reactive or exhibit all characteristic properties.
Practice preview
Which of the following ions is colourless?…
medium
Which of the following is NOT a characteristic property of transition elements?…
easy
The general electronic configuration of d-block elements is:…
easy