3.2.5 Transition metals (A-level only) Flashcards
Where do the d block elements sit on the periodic table?
In the middle of the periodic table
What is a transition metal
A d-block element that can form at least one stable ion with a partially filled d-subshell
What are two metals that are not transition metals?
Zinc and Scandium
Why is scandium not a transition metal? [2]:
- Scandium only forms 1 stable ion of Sc³⁺
- It has an EMPTY d-subshell
Why is zinc not a transition metal? [2]:
- It only forms one stable ion of Zn²⁺
- It has a FULL d-subshell
Properties of transition metals [4]:
- Variable oxidation states
- Partially full d-subshell
- Coloured ions in solution
- Good catalysts
Why do transition metals have variable oxidation states?
[2]:
- electrons sit in 4s and 3d energy levels which are very close
- so electrons are gained and lost using a similar amount of energy
What does Iron(II) look like as an aqueous ion?
Green solution
What does Copper(II) look like as an aqueous ion?
Blue solution
What does Iron(III) look like as an aqueous ion?
Purple solution but may look brown/yellow cus of [Fe(H₂O)₅(OH)]²⁺₍ₐᵩ₎
What is an example of a transition metal being a good catalyst? [2]:
- Iron in the Haber process
- Nickel or Platinum in hydrogenation
What does Aluminium(III) look like as an aqueous ion?
Colourless solution
What does Iron(II) look like due to the action of NaOH?
green precipitate that goes brown on standing in air
What does Copper(II) look like due to the action of NaOH?
Blue precipitate
What does Iron(III) look like due to the action of NaOH?
Brown precipitate / may look orangey brown
What does Aluminium(III) look like due to the action of NaOH?
White Precipitate
What does Iron(II) look like due to the action an excess of NaOH(aq)?
No further change
What does Copper(II) look like due to the action an excess of NaOH(aq)?
No further change
What does Iron(III) look like due to the action an excess of NaOH(aq)?
No further change
What does Aluminium(III) look like due to the action an excess of NaOH(aq)?
Colourless solution
What does Iron(II) look like due to the action of NH3(aq)?
green ppt goes brown
on standing in air
What does Copper(II) look like due to the action of NH3(aq)?
blue ppt
What does Iron(III) look like due to the action of NH3(aq)?
No further change
What does Aluminium(III) look like due to the action of NH3(aq)?
No further change
What does Iron(II) look like due to the action an excess of Na2CO3(aq)?
green ppt
What does Copper(II) look like due to the action an excess of Na2CO3(aq)?
blue-green ppt
What does Iron(IlI) look like due to the action an excess of Na2CO3(aq)? [3]:
- brown ppt
- (ppt may look orange-brown)
- and CO2 gas evolved
What does Aluminium(IlI) look like due to the action an excess of Na2CO3(aq)? [2]:
- white ppt
- CO2 gas evolved
Transition metal ions use…
vaccant, hybridised 4s, 4p, 4d orbitals to accept ligand coordinate bonds
Ligand [definition]:
A species with a lone pair
Coordinate bonds [explanation]:
Lone pair on ligand accepted by vacant orbitals
How many lone pairs do transition metal ions accept? [2]:
- 4 lone pairs/ ligands
- 6 lone pairs/ ligands
Monodentate =
1 lone pair per ligand so can only form one coordinate bond
Examples of monodentate ligands [4]:
- Water
- NH3
- Cl-
- CN-
Bidentate =
2 LPs per ligand so form 2 coordinate bonds
Example of bidentate logo =
H₂NCH₂CH₂NH₂
Multidentate =
Multiple lone pairs that can be used to make ligands/ multiple coordinate bonds per ligand
Example of multidentate ligand =
EDTA⁴⁻
What are the shapes of complex ions [4]:
- Octahedral
- Tetrahedral
- Square planar
- Linear
Octahedral complex ions [3]:
- 6 coordinate bonds
- 90° bond angle
- Most common shape
What is the coordination number of an octahedral ion?
6
How do you work out the coordination number?
Count the no. of coordinate bonds
Tetrahedral complex ions [3]:
- 4 coordinate bonds
- 109.5° bond angle
- Seen when ligands are large and charged
Square planar complex ion [2]:
- 4 coordinate bonds
- 90° bond angle
What is the coordinate number for a tetrahedral ion?
4
What is an example of a square planar complex ion?
CISPLATIN
What is the coordination number of a square planar ion?
4
Linear complex ions [2]:
- 2 coordinate bonds
- 180° bond angle
What is the coordination number for a linear complex ion?
2
What is an example of a linear complex ion?
Tollen’s reagent
