TRANSITION ELEMENTS Flashcards
WHAT IS THE ORDER OF SUB SHELLS IN INCREASING ENERGY
1s 2s 2p 3s 3p 4s 3d 4p 4d
What is a transition element
a d block element that can form at least one stable ion with a partially filled d subshell
Which period 4 metals are not transition elements
scandium and zinc as they don’t form a stable ion
Which 2 transition metals form a 4s1 shell
Copper and Chromium
as an electron in the 4s sub shell will jump to form a half filled or fully filled 3d shell that is more stable
Why is scandium not a transition element
as its only stable ion (Sc3+) has an empty d subshell, which is not partially filled
Why is Zinc not a transition element
As it has one stable ion (Zn2+) which has a fully filled d subshell, which is not partially filled
3 properties of transition metals
variable oxidation states - as electrons sit in 4s and 3d sub shells
form coloured ions in solution
good catalysts
Vanadium ions and their colours
V2+ - violet
V3+ - green
VO2+ - blue
VO3+ - yellow
Chromium ions and their colours
Cr3+ - green/violet
Cr2O72- - orange
Manganese ions and their colours
Mn2+ - pale pink
MnO42- - green
MnO4- - purple
Iron ions and their colours
Fe2+ - pale green
Fe3+ - yellow
Cobalt ions and their colours
Co2+ - pink
Nickel ions and their colours
Ni2+ - green
Copper ions and their colours
Cu2+ - blue
Titanium ions and their colours
Ti2+ - violet
Ti3+ - purple
How are transition metals good catalysts
they can receive and lose electrons in the d - orbital to speed up reactions
they allow substances to aDsorb to their surfaces which lowers the activation energy of a reaction
Risks of transition elements as catalysts
Long term exposure of copper can cause liver damage
long term exposure to manganese can cause physical tremors
Cu2+ with OH- or NH3
and addition of OH- to precipitate
Addition of NH3 to precipitate
pale blue precipitate
Cu(OH)2(H2O)4
insoluble in excess NaOH so no change
Dark blue solution( part ligand substitution)
[Cu(NH3)4(H2O)2]2+
Fe2+ with OH- or NH3
and addition of OH- to precipitate
Addition of NH3 to precipitate
Dirty green precipitate
Fe(OH)2(H2O)4
insoluble in excess NaOH so no change
insoluble in excess NH3 so no change
Fe3+ with OH- or NH3
and addition of OH- to precipitate
Addition of NH3 to precipitate
Orange - brown precipitate
Fe(OH)3(H2O)3
insoluble in excess NaOH so no change
insoluble in excess NH3 so no change
Mn2+ with OH- or NH3
and addition of OH- to precipitate
Addition of NH3 to precipitate
Pink precipitate
Mn(OH)2(H2O)4
insoluble in excess NaOH so no change
insoluble in excess NH3 so no change
Cr3+ with OH- or NH3
and addition of OH- to precipitate
Addition of NH3 to precipitate
Green-grey precipitate
Cr(OH)3(H2O)3
Dark green solution
Cr(OH)63-
Purple solution(full ligand substitution)
[Cr(NH3)6]3+
What is the structure of a metal complex
A central transition metal ion is surrounded by ligands bonded by dative covalent bonds
this is because the ligands have at least one lone pair so both electrons in the bond come from the ligand
What is a ligand and the three types
an ion, atom or molecule with at least one lone pair of electrons
monodentate, bidentate and polydentate
the 4 monodentate ligands
H2O 6
NH3 6
CN- 6
Cl- 4
The two bidentate ligands
ethanedioate
ethane-1,2-diamine
What is the coordination number
the number of coordinate bond in a complex
bond angles in an octahedral complex
90 degrees
Shape and bond angle of cisplatin
square planar and 90 degrees
Structure of cisplatin
an anti cancer drug
square planar complex with platinum metal ion, 2 ammonia ligands and 2 chloride ion ligands
How does cis platin cause death of cancer cells
the chloride ligands will be easily displaced from cis platin, and the cis platin molecule will bind to the nitrogen atoms on the DNA in the cancer cell
as the complex is attached to the DNA it prevents the cell from reproducing by cell division so the cell will die
What is a disadvantage of cis platin
it can also prevent healthy cell replication which will increase the risk of infection and kidney damage
What factors will change the colour of a complex ion
change of oxidation state
change in coordination number
change in ligand
Structure of haemoglobin
Octahedral complex, 4 nitrogen are from the multidentate ligand haem, one nitrogen on the bottom is from a globin protein, and an oxygen or water molecule that is co-ordinately bonded at the top
Why is carbon monoxide poisonous
If carbon monoxide is inhaled the water ligand on haemoglobin is replaced with a CO ligand
this forms a very strong co ordinate bond so its not readily replaced by oxygen or water
therefore less oxygen can be transported and leads to oxygen starvation in organs
Colour change with addition of NaOH to Cu2+
pale blue precipitate
Colour change with addition of NaOH to Fe2+
green precipitate
Colour change with addition of NaOH to Fe3+
orange precipitate
Colour change with addition of NaOH to Mn2+
pale brown precipitate
Colour change with addition of NaOH to Cr3+
dirty green precipitate
Why is nitric acid added before silver nitrate when testing for halides
to react with any other anions other than the halides
to prevent a false result
[Cu(H2O)6]2+ Colour
blue solution
[Cu(OH)2(H2O)4] colour
blue precipitate
[Cu(NH3)4(H2O)2]2+ colour
deep blue solution
[CuCl4]2- colour
yellow solution
[Fe(H2O)6]2+ colour
pale green solution
[Fe(OH)2(H2O)4] colour
dark green solution
[Fe(H2O)6]3+ colour
yellow solution
[Fe(OH)3(H2O)3] colour
orange-brown precipitate
[Mn(H2O)6]2+ colour
very pale pink
[Mn(OH)2(H2O)4] colour
light brown precipitate
[Cr(H2O)6]3+ colour
violet solution
[Cr(OH)3(H2O)3] colour
grey green precipitate
[Cr(OH)6]3- colour
dark green solution
[Cr(NH3)6]3+ colour
purple solution
