D block elements Flashcards
Sc3+
Colourless
Ti4+
Colourless
Cr3+
Violet
Mn2+
Pale pink
Fe3+
Brown yellow
Fe2+
Pale green
Co2+
Pink
Ni2+
Green
Cu2+
Blue
Cu+
Colourless
Zn2+
Colourless
MnO4-
-
Purple
MnO42-
Green
CrO42-
Yellow
Cr2O72-
Orange
Transition and non-transition d block elements
d block elements contain incompletely filed d subshell at elemental state or with the ability to form at least one stable ion with incompletely filled d subshell are called transition elements. Therefore, d block elements producing ions only with d10 configurations are considered as non-transition elements.(Zn,Cd,Hg)
Properties of transition elements
Has less variations in atomic radii than main group elements. The atomic radii decreases slightly and then increase.
Nuclear charge increases across a group.
But at the end elements like Zn, Cu atomic radii increases as repulsion between electrons are high due to the pairing of electrones.
Which d block element has the highest melting point
Cr- theoretical value
V- practically
Higher the number of unpaired electrons higher the melting point (refer)
Mn3+
Violet
V2+
violet
V3+
green
Ti3+
purple
NO
nitrosyl- neutral
CO
carbonyl- neutral
C2H5N
pyridine-neutral
MnO2
Dark brown/black
under acidic conditions, MnO4- reduces to
Mn2+.
H3O+
Hydronium
What is coordination number
The no. of coordination bonds formed between the central metal ion and ligands.
Depends on size, charge, nature of the ligand and the electronic configuration of the central metal ion.
Factors affecting the color of complexes
Central metal ion, oxidation state of the central metal ion and the nature of the ligand
Colors of complexes
Aqueous
Same color as the metal ion
Cr(OH)3
Blue-green
Mn(OH)2
white/ cream
Fe(OH)2
Dirty green
Fe(OH)3
Reddish-brown
Co(OH)2
Pink
[Co(OH)4]2-
Deep-blue
Ni(OH)2
green
Cu(OH)2
Blue
Zn(OH)2
white
[Zn(OH)4]2-
Colorless
Cr(OH)3 -NH3
Blue-green
Mn(OH)2 -NH3
White/ cream
Fe(OH)2 -NH3
Dirty green ppt
Fe(OH)3 -NH3
Reddish-brown ppt
[Co(NH3)6]2+
yellowish-brown
[Co(NH3)6]3+
Brownish-red
[Ni(NH3)6]2+
Blue
[Cu(NH3)4]2+
Deep blue
[Zn(NH3)4]2+
Colourless
[CrCl6]3-
Blue-violet
[MnCl4]2-
Greenish yellow
[FeCl4]-
Yellow
[Co(Cl)4]2-
Blue
[NiCl4]2-
Yellow
[CuCl4]2-
Yellow
[ZnCl4]2-
Colourless
[Cr(H2O)6]3+ + 3NH3 (aq)
Cr(OH)3(s) + 3NH4+(aq) + 3H2O(l)
Blue-green gelatinous ppt
[Co(H2O)6]2+(aq) + 2OH-(aq)
Co(OH)2(s) + 6H2O(l)
Pink ppt
Co(OH)2(s) + 2OH-(aq)
[Co(OH)4]2-(aq)
Deep blue solution
[Co(H2O)6]2+(aq) + 6NH3 (aq)
[Co(NH3)6]2+(aq) + 6H2O(l)
Forms a yellowish-brown solution however due to the auto oxidation it forms[Co(NH3)6]3+(aq) which is brownish-red in colour.
Co(H2O)6]2+(aq) + 4Cl-(aq)
[CoCl4]2-(aq) + 6H2O(l)
Forms a blue solution
[Ni(H2O)6]2+(aq) + 2OH-(aq)
Ni(OH)2(s) + 6H2O(l)
Forms a green precipitate
[Ni(H2O)6]2+(aq) + 6NH3 (aq)
[Ni(NH3)6]2+(aq) + 6H2O(l)
Forms a deep-blue solution
[Ni(H2O)6]2+(aq) + 4Cl-(aq)
[NiCl4]2-(aq) + 6H2O(l)
Forms a yellow solution
[Mn(H2O)6]2+(aq) + 2OH-(aq)
Mn(OH)2(s) + 6H2O(l)
Forms white/cream ppt
[Fe(H2O)6]3+(aq) + 3OH-(aq)
Fe(OH)3(s) + 6H2O(l)
Forms reddish-brown ppt
[Cu(H2O)6]2+(aq) + 2OH-(aq)
Cu(OH)2(s) + 6H2O(l)
Pale blue solution turns into blue solution
[Cu(H2O)6]2+(aq) + 4NH3(aq)
[Cu(NH3)4]2+(aq) + 6H2O(l)
Forms a deep-blue complex
[Cu(H2O)6]2+(aq) + 4Cl-(aq)
[CuCl4]2-(aq) + 6H2O(l)
Solution turns yellow
[Zn(H2O)6]2+(aq) +2OH-(aq)
Zn(OH)2(s) + 6H2O(l)
Colorless solution turns in to a white precipitate.
Metal cations which forms precipitates with Cl
Pb
Ag
Hg
Colors of carbonates formed by group 2 metals
All carbonates formed by group 2 metals are white.
