transition metals Flashcards
(69 cards)
What is a transition element?
A d-block element that can form at least one stable ion with a partially filled d-subshell.
What are the general physical properties of transition metals?
- Good conductors of heat and electricity
- Hard
- Strong
- Shiny
- High melting points
- High boiling points
What are the general chemical properties of transition metals?
- Form complex ions
- Form coloured ions
- Good catalysts
- Variable oxidation states
What is the order of filling electron subshells in transition metals?
4s sublevel fills up first, followed by the 3d sublevel.
Which two elements are exceptions in the electron configuration pattern of transition metals?
Chromium (Cr) and Copper (Cu).
Why are Scandium and Zinc not considered transition metals?
They only form Sc3+ (3d10) and Zn2+ (3d10) respectively, resulting in empty or full d subshells.
What is a complex ion?
A transition metal ion surrounded by ligands bonded to it by coordinate bonds.
What defines a ligand?
A molecule or ion that forms a coordinate bond with a transition metal by donating a pair of electrons.
What is the coordination number?
The number of coordinate bonds to ligands that surround the d-block metal ion.
What are the types of ligands based on coordination?
- Uni/Monodentate ligands
- Bidentate ligands
- Multidentate ligands
What is the chelate effect?
The phenomenon where monodentate ligands are replaced by bi/multidentate ligands, forming more coordinate bonds.
What is the shape of octahedral complexes?
Coordination number of 6 with bond angles of 90 degrees.
How does the substitution of similar sized ligands occur?
Without change of coordination number or shape.
What happens during the substitution of different sized ligands?
Change of coordination number and shape occurs.
What is the effect of ligand substitution on enthalpy?
Enthalpy change is often small as the strength of the bonds broken is similar to the new bonds formed.
What is the significance of multidentate ligands in stability?
They form more stable complexes due to ring structures, which are thermodynamically and kinetically stable.
What is optical isomerism?
Occurs when there are two or more bidentate ligands in a complex that is octahedral.
Why are transition metal complexes colored?
Due to their partially filled d-orbitals allowing electrons to be promoted by absorbing UV/visible light.
What is the formula for calculating ΔE?
ΔE = hν = hc/λ
What does a high frequency of light correspond to in terms of color?
Violet light, which has high energy.
What is the overall charge on a complex ion determined by?
The total oxidation state of the metal ion and the sum of the ligand charges.
What is the bond angle in tetrahedral complexes?
109.5 degrees.
What is the bond angle in square planar complexes?
90 degrees.
Fill in the blank: A ligand that forms 1 coordinate bond to a metal ion is called a _______ ligand.
monodentate