5: Properties of Transition Metals and Ligands Flashcards
What is the definition of a transition metal?
Metals that can form one or more stable ions with an incomplete D sub shell.
Which 2 elements do not count as transition elements?
Scandium and Zinc
Why are scandium and zinc not considered transition metals?
They do not form ions with incomplete d subshells.
Give the shortened electron configuration of chromium.
[Ar] 4s1, 3d5
Give the shortened electron configuration of copper.
[Ar] 4s1 3d10
For copper and chromium, why does the 4s subshell not fill fully?
The atom is more stable when the 3d subshell is either full or half full.
Give the shortened electron configuration of Cu2+
[Ar] 3d9
Give 2 physical properties of transition metals.
High density
High melting/boiling point
What type of ions can transition elements form?
Complex
What can transition metal ions do that normal metal ions can’t do?
They can form coloured ions.
Why can transition metals form ions with different charges?
They have variable oxidation states
What is a complex ion?
An ion formed when a transition metal is surrounded by ligands that bond to it by donating lone pairs into vacant d orbitals
Ligands always form which type of bonds?
Coordinate bonds
What are ligands?
Atoms or ions that have a lone pair to form a coordinate bond with other metals.
What is the coordination number?
The number of coordinate bonds formed by ligands to metal ions.
What is a unidentate ligand?
Give some examples.
Ligands that form one coordinate bond.
NH3, :Cl-, :CN-
In Ag+ complexes, what shape will the ion be?
What will the bond angle be?
What will the coordination number be?
Linear
180 degrees
Coordination number 2
In large ligands (eg: :Cl-), what shape will the ion be?
What will the bond angle be?
What will the coordination number be?
Tetrahedral
Bond angle 109.5
Coordination number 4
In Pt2+ complexes, what shape will the ion be?
What will the bond angle be?
What will the coordination number be?
Square planar
90 degrees bond angle
Coordination number 4, 2 lone pairs
In most complex ions, what shape will the ion be?
What will the bond angle be?
What will the coordination number be?
Octahedral
Bond angle 90
Coordination number 6
What are bidentate ligands?
Ligands that form 2 coordinate bonds
Give 2 examples of bidentate ligands.
En, (C2O4 2-)
What is another name for complex ions that form a multidentate ligand?
Chelate
Chelates can be used to remove d block metal ions from what?
Remove them from solution
Name the element that creates a ligand in haem groups.
This atom froms the complex called g_____
Nitrogen. Forms part of the globin complex.
Why is the binding of oxygen to haemoglobin reversible?
The bond between the iron ion and oxygen is weak, so oxygen easily be unloaded where needed.
Why is the binding of CO to haemoglobin irreversible?
CO is a ‘better ligand’.
Describe how optical isomerism works in ligands with different atoms.
Ligands will be on different atoms.
Finish the substitution reaction equation for
[Co(H2O)6]2+ + 6NH3
[Co(H2O)6]2+ + 6NH3 -> [Co(NH3)6]2+ + 6H2O
Finish the substitution reaction equation for [Cu(H2O)6]2+ + 4Cl-
[Cu(H2O)6]2+ + 4Cl- -> [CuCl4]2- + 6H2O
Finish the substitution reaction equation for [Cu(H2O)6]2+ + 4NH3
[Cu(H2O)6]2+ + 4NH3 -> [Cu(H2O)2(NH3)4]2+ + 4H2O
Why is the reaction with CN- ligands irreversible?
It forms strong bonds
What type of isomerism can complex ions with a square planar shape and octahedral shape show?
E/Z
Describe arrangement of ligands in a cis isomer of an octahedral complex ion.
If the 2 different ligands to the other 4 are next to each other, it is cis.
Describe arrangement of ligands in a trans isomer of an octahedral complex ion.
If the 2 ligands that are different to the other 4 are opposite each other, it is trans.
Finish the ligand substitution equation for this reaction:
[Fe(H2O)6]3+ + 6CN-
[Fe(H2O)6]3+ + 6CN- -> [Fe(CN)6]3- + 6H2O
For most substitution reactions, is enthalpy likely to be positive or negative?
Negative
Finish the substitution equation for this reaction.
[Cu(H2O)6]2+ + 3en
[Cu(H2O)6]2+ + 3en -> [Cu(en)3] + 6H2O
Explain why entropy increases for this reaction:
[Ni(NH3)6]2+ + 3en -> [Ni(en)3]2+ + 6NH3
State the feasibility of this reaction.
There are more molecules on the right than the left. This means the reaction will always be feasible.
