Transition Metals Intro Flashcards
What is a transition metal?
A D block element that forms 1 or more stable ion with incompletely filled d orbitals
What is a d block element?
The highest energy electron is in the d orbital
What does it mean for the d orbitals to be incompletely filled (to be considered a transition metal)?
The d subshell overall has less than 10 electrons when it has formed the ion
Are all d block elements transition metals? Why/why not?
No if they can’t form at least 1 stable ion with an incompletely filled d orbital then it is not a transition metal
What d block elements are NOT transition metals? And why?
Zn and Sc because the only ions they form have completely filled d orbitals or completely empty
If an element can form both an ion with a partially filled d subshell, but also an ion with a completely filled d subshell is it a transition metal?
Yes as long as it can from 1 ion at least with an incompletely filled d subshell it counts regardless of what the other ions electron configuration is
Characteristics of transition metals
*complex formation
*formation of coloured ions
*variable oxidation state
*catalytic activity
When forming ions, electrons in what subshell are lost first?
In 4s
Complex
A central transition metal ion bonded to ligands (ions or molecules) by dative bonds
Ligand
Species (ion or molecule) with a lone pair which is able to form co-ordinate bonds with transition metal ions
How do ligands bond to complex ions?
By dative bonds
So in the bonding pair of electrons, both electrons are from the ligand and shared with empty d orbitaal in the transition metal ion
What subshell is filled first when writing electron configurations for transition metal ATOMS?
4s THEN 3d
What transition metals are exceptions to 4s/3d filling rule
Cr and Cu
Both have 1 4s electron and rest in 3d
Oxidation state
Shows the number of electrons lost or gained by an atom relative to its atomic state
Because transition metal atoms have variable oxidation states then…
They are able to both donate and receive electrons
So can therefore acts as either reducing and oxidising agents
What atoms tend to act as reducing agents?
Elements that have ions of a smaller oxidation state eg Fe2+ are more likely to lose electrons so REDUCE another
What atoms tend to act as oxidising agents?
Elements that have ions of a greater Oxidation state eg Mn 7+ are more likely to gain electrons so OXIDISE another
When do transition metal atoms form different oxidation states?
When forming a compound, form bonds to other atoms eg MnO4-
Determines the number of electrons gained/lost from atom relative to its atomic state
Main energy transfers when forming a compound (thus determine oxidation state of a transition metal atom)
Sum of each IE of transition metal to form its ion
—-> Amount of energy required to put into atom to lose electron (breaking bond between electron to atom is endo)
Amount of energy released when the compound forms
—-> Making bonds is exothermic
What energetic process is favoured when forming an ionic lattice?
One that releases most energy because a more stable compound is formed
So if enough energy is released by LEform to offset sum of IE
Why can transition metal atoms form multiple oxidation states but group1/2/3 cant in terms of energetics?
Electrons in TM lost from 4s/3d subshells with little difference in energy between orbitals so sum of ie to lose electrons is likely to be smaller, so likely to be offset by energy released when making bonds SO LIKELY TO LOSE multiple electrons = multiple OX states
Big energy jumps between subshells in group 1/2, IE sum too high so not likely to be offset
Coordination number of a transition metal ion in a complex
the number of co-ordinate bonds accepted by that ion.
3 Types of ligand
Monodentate
Bidentate
Multidentate
Monodentate ligand meaning
a species that is only able to form one co-ordinate bond to a transition metal ion.
