Transition elements
OCR-A LEVEL CHEMISTRY
MODULE 5
d-block elements that form at least 1 ion with a partially filled d-orbital
1) Sc forms only Sc ³+
Sc³+: 1s² , 2s², 2p⁶ , 3s² , 3p⁶
Sc³+ has empty d-orbitals = NOT a transition element by definition
2) Zn only forms Zn²+
Zn²+ : 1s² , 2s², 2p⁶ , 3s² , 3p⁶, 4s², 3d¹⁰
Zn²+ has fully filled d-orbitals = NOT a transition element by definition
But they’re still d-block elements
Properties
Due to incomplete d-orbitals :
● Conductors of heat and electricity
● Shiny, stronger and harder than group 2 metals
● High melting and boiling points
Variable oxidation states
Number of oxidation states increases across the period up to Mn, then decreases
All transition metals form compounds with an oxidation number of 2
Each oxidation state has a characteristic colour
1
, The higher the oxidation state, the stronger the oxidising agent
Uses as catalysts
Outer shell electrons (highest energy) are easily lost or gained
The oxidation state fluctuates as electrons are accepted or donated
This increases the speed of electron transfer
+ Reduces energy usage (used at lower temperatures)
- Toxic transition elements
Eg. Cu = liver damage
Mn = physical tremors
2
OCR-A LEVEL CHEMISTRY
MODULE 5
d-block elements that form at least 1 ion with a partially filled d-orbital
1) Sc forms only Sc ³+
Sc³+: 1s² , 2s², 2p⁶ , 3s² , 3p⁶
Sc³+ has empty d-orbitals = NOT a transition element by definition
2) Zn only forms Zn²+
Zn²+ : 1s² , 2s², 2p⁶ , 3s² , 3p⁶, 4s², 3d¹⁰
Zn²+ has fully filled d-orbitals = NOT a transition element by definition
But they’re still d-block elements
Properties
Due to incomplete d-orbitals :
● Conductors of heat and electricity
● Shiny, stronger and harder than group 2 metals
● High melting and boiling points
Variable oxidation states
Number of oxidation states increases across the period up to Mn, then decreases
All transition metals form compounds with an oxidation number of 2
Each oxidation state has a characteristic colour
1
, The higher the oxidation state, the stronger the oxidising agent
Uses as catalysts
Outer shell electrons (highest energy) are easily lost or gained
The oxidation state fluctuates as electrons are accepted or donated
This increases the speed of electron transfer
+ Reduces energy usage (used at lower temperatures)
- Toxic transition elements
Eg. Cu = liver damage
Mn = physical tremors
2
