Transition Metals Flashcards
(24 cards)
What is a transition metal?
it forms at least one stable ion with a part-full d-shell of electrons.
Why are scandium and zinc not transition metals although they are in the d-block?
Scandium only formt eh ion Sc£+ which has an empty d-shell and zinc only forms Zn2+ which has a full d-shell.
Why are chromium and copper more sable than expected?
They only have one electron in the 4s outer shell. In chromium the d-shell is half-full and in copper it is full
What are the 4 main properties of transition metals?
- Form complex ions,
- Are coloured,
- Have variable oxidation states,
- Acts as catalysts.
What is a complex ion?
When 2, 4 or 6 ligands are bound to a transition metal.
What is the co-ordination number?
The number of ligands that surround the metal ion.
What is a multidentate ligand?
When there is more than one atom with a lone pair of electrons binding to the transition metal.
Give an example of a hexadentate ligand
EDTA 4-
What is the chelate effect?
When ligands are added to a solution of a transition metal salt with the result being more entities (an increase in entropy)
What is the shape of ions with a co-ordination number of 6?
Octehedral
What is the shape of ions with a co-ordination number of 4?
Tetrahedral and square planar
Why is there a difference in shape between [CoCl4]2- and [Co(NH3)6]3+?
The chloride ion is larger so only four Cl-‘s can fit around the meta ion whereas there is room for 6 NH3’s.
Give an example of a linear complex ion.
[Ag(NH3)2]+
What forms of isomerism do transition metals show?
Geometrical and optical.
When do transition metal complexes form optical isomers?
When they have 2 or more bidentate ligands.
Why are transition metal elements coloured?
They have a part-filled d-orbital so electrons can move from one d-orbital to another. When electrons move from one d-orbital to another with a slightly higher energy level they absorb energy from the visible region of the spectrum . This colour is then missing from the spectrum and what you see is the combination of the not absorbed colours.
How do you calculate change in energy?
Planck’s constant x frequency or Planck’s constant x velocity of light / wavelength.
Why can transition metals have so many oxidation states?
A typical transition metal can use its 3d electrons as well as its 4s electrons.
What is the ratio of Fe2+ reacting with manganate [VII]?
5 : 1
In what ratio do MnO4- ions react with C2O42- ions?
2 : 5
Give an example of a linear complex ion
[Ag(NH3) 2]+
Give an example of a tetrahedral complex ion
[CoCl4] 2-
Give an example of a square planar complex ion
[NiCN4] 2-
Give an example of an octahedral complex ion
[Co(NH3)6]3+
