chemistry - unit 1.3 Flashcards
What are the d-block transition metals?
Metals with an incomplete d subshell in at least one of their ions.
What does the filling of the d-orbitals follow?
The aufbau principle, with the exception of chromium and copper atoms.
What are these exceptions due to?
The special stability associated with the d subshell being half-filled or completely filled.
When atoms from the first row of the transition elements form ions, which electrons are lost first?
The 4s electrons that are lost first rather than the 3d electrons.
When is an element said to be in a particular oxidation state?
When it has a specific oxidation number.
What do uncombined elements have an oxidation number of?
0
What do ions containing single atoms have an oxidation number of?
The same as the charge on the ion.
In most of its compounds, what does oxygen have an oxidation number of?
-2
In most of its compounds, what does hydrogen have an oxidation number of?
+1
What must the sum of all the oxidation numbers of all the atoms in a neutral
compound add up to?
0
What must the sum of all the oxidation numbers of all the atoms in a polyatomic ion equal?
The charge on the ion.
What can a transition metal have?
Different oxidation states in its compounds.
What may compounds of the same transition metal in different oxidation states have?
Different colours.
What can oxidation be defined as?
An increase in oxidation number.
What can reduction be defined as?
A decrease in oxidation number.
What can be used to determine whether oxidation or reduction has occurred.
Changes in oxidation number of transition metal ions.
What are compounds containing metals in high oxidation states often?
Oxidising agents, whereas compounds with metals in low oxidation states are often reducing agents.
What are ligands?
They may be negative ions or molecules with non-bonding pairs of electrons that they donate to the central metal atom or ion, forming dative covalent bonds.
What can ligands be classified as?
Monodentate, bidentate, up to hexadentate.
How can you deduce the ligand classification?
From a formula or structure of the ligand or complex.
What is known as the coordination number?
The total number of bonds from the ligands to the central transition metal.
In a complex of a transition metal, what are the d-orbitals?
No longer degenerate.
When does splitting of d-orbitals to higher and lower energies occur?
When the electrons present in approaching ligands cause the electrons in the orbitals lying along the axes to be repelled.
What do you call ligands that cause a large different in energy between subsets of d-orbitals?
Strong field ligands.
