Transition Metals Flashcards
What is the ‘best’ definition of a transition metal?
That a translation metal has at least one ion with an incomplete d-subshell (bar Sc and Zn)
What two metals (from the top row of transition metals) are excempt from most transition metal rules ?
Zinc and Scandium
What are the properties of transition metals?
They are found in the d-block of the periodic table; they usually have an incomplete d-subshell; each has at least one ion with an incomplete d-subshell; they can produce different valencies ; they can produce coloured compounds; and they can act as catalysts. *all except Sc and Zn.
Which two transition metals fill their 4s and 3D orbitals differently than usual?
Cr - 4s^1 3d^5
Cu - 4s^1 3d^10
Why are copper and chromiums 4s orbitals only 1/2 filled ?
There is extra stability in the 3d orbital gained by filling or 1/2 filling it. Simultaneously the 4s orbital is still stable as it is 1/2 full
Transition metals exist in…
Variable oxidation states of differing stability
Why do transition metals exist in variable oxidation states?
They can loose all their electrons from their 4s orbital as well as some or sometimes all of their 3d orbital electrons
How can electron configurations be used to explain oxidation states ?
They can often show which oxidation state would be more stable for the orbitals in the atom to form.
(With the exception of Cu^2+ kind which form in the place of Cu^+ ions even though the Cu^+ ions are more stable
What can oxidation numbers keep track of?
They can help keep track of electrons
What is the assumed oxidation number of oxygen ?
2-
What is the assumed oxidation number of hydrogen?
+1
What are ligands?
An atom,molecule or ion that contains at least one lone pair
What are transition metal complexes ?
A metal atom or ion surrounded by ligands with the ligands bound to the metal through co-ordinate covalent bonds
How do metals form transition metal complexes ?
The metals make use of empty hybrid orbitals, usually involving at least some d-orbital
What is a dative covalent bond ?
When both the electrons making a covalent bond come from the same atom.
Is a dative covalent bond the same as a co-ordinate covalent bond ?
Yes
Why are ligands described as dentate?
The ligands are considered to bite the metal ion
How can ligands be classified ?
By the number of bonds they can make with a central atom or ion.
What is a monodentate ligand ?
Ligands that can only form 1 bond with a metal atom
What are examples of molecules containing monodentate ligands ?
NH3 , Cl^- , CN^- ( a cyanide ion) and H2O
How do ligands bond to metal ions ?
By donating one or more electron pairs into unfilled metal orbitals
What are bidentate ligands ?
Ligands that can form 2 bonds with a metal atom/ion
What are examples of molecules containing bidentate ligands ?
Ethylenediamine
Oxalate ions
What are polydentate ligands ?
Ligands that can form many bonds with a metal atom or ion
