Transition Elements Flashcards
What is different about chromium and copper?
They fill d orbitals before s orbitals
Why can transition metals form ions with different oxidation states?
Easy to lose 4s electrons and 3d electrons as the difference in energy is very small between the 4s and 3d orbitals.
What oxidation state is most common at the start of the d block?
+3
What oxidation state is most common at the end of the d block?
+2
How can transition elements act as a homogeneous catalyst?
Variable oxidation states - Solution of metal can act as a catalyst in aqueous reactions.
How can transition elements act as a heterogeneous catalyst?
Empty/available d orbitals at the correct energy level to accept electrons.
What is the catalyst in the contact process?
V
What is the catalyst in the Haber process?
Finely divided Fe
What is the catalyst in the hydrogenation of alkenes?
Use Ni/Pt catalyst
What is the catalyst in the decomposition of Hydrogen peroxide?
Co
What is the definition of transition elements?
A d block element that forms at least one ion with an incomplete d sub-shell.
What are the chemical properties of transition elements?
Form compounds with variable oxidation states
Form coloured compounds
Both elements and their compounds are good catalysts
What are the physical properties of transition elements?
Dense Durable Ductile Malleable High boiling points High tensile strength High melting points
Where are lower oxidation states normally found?
Simple ionic compounds
Where are higher oxidation states normally found?
Molecular ions
When are d block elements coloured in aqueous solution?
When they have a partially filled d orbital.
What is the definition of a complex ion?
A transition metal ion bonded to one or more ligands by coordinate bonds.
What is the definition of a ligand?
A molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond
What are examples of neutral monodentate ligands?
Water
Ammonia
What are examples of charged monodentate ligands?
Hydroxide
Thiocyanate
Cyanide
Chloride