Transition elements, OCR- Unit 5 module3

Transition elements, OCR- Unit 5 module3

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  • Created on: 13-05-12 18:30
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Sameer Biology
Jahabarali
Unit 5 Modul
e 3 Tr
ansi
t
ion
element
s
Transition metals are d-block elements (elements that fill electron in the D sub-shell) that form at least one
ion with an incomplete d sub-shell. Most elements in the d-block are transition elements except:
Scandium- only forms Sc3+ ion in which the d-orbitals are empty
Zinc- only form Zn2+ ion, I which the d-orbitals are completely full
Electron configuration is the arrangement of electrons in order of
energy level occupied (orbitals and subshells).
Element Z (number of Electron
s electrons) configuratio
n
Sc 21 [Ar] 4s2 3d1
Ti 22 [Ar] 4s2 3d2
V 23 [Ar] 4s2 3d3
Cr 24 [Ar] 4s1 3d5
Mn 25 [Ar] 4s2 3d5
Fe 26 [Ar] 4s2 3d6

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Sameer Biology
Jahabarali
Unit 5 Modul
e 3 Tr
ansi
t
ion
element
s
Co 27 [Ar] 4s2 3d7
Ni 28 [Ar] 4s2 3d8
Cu 29 [Ar] 4s1 3d10
Zn 30 [Ar] 4s2 3d10
Properties of transition metals include:
Metallic properties
Variable oxidation states- Transition elements (Ti-Cu) all form ions with two or more oxidations
states. they easily lose 4s electrons first as it is the highest occupied energy level, but also 3d
electrons since both energy levels are so close.…read more

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Sameer Biology
Jahabarali
Unit 5 Modul
e 3 Tr
ansi
t
ion
element
s
Ligands Formula Change
water :OH2 Neutral
Ammonia :NH3 Neutral
Thiocyanat :SCN- -1
e
Cyanide :CN- -1
chloride :Cl- -1
hydroxide :OH- -1
Complex ions are formed within a solution when a central metal ion is surrounded by one or more ligands,
which are molecules, or an ions that donate and electron pair to the central metal ion, by coordinate bonds
(dative covalent in a transition metal).…read more

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Sameer Biology
Jahabarali
Unit 5 Modul
e 3 Tr
ansi
t
ion
element
s
Optical isomers- forms in octahedral complexes containing multidentate ligands when:
o A complex with three bidentate ligand
o A complex with two bidentate ligand and two monodentate ligand
o A complex with one hexadentate ligand
Cis-platin is and isomer of complex ions that can be used as a cancer drug. It is active by binding to the DNA
in cancer cells preventing mitosis from taking place.…read more

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Sameer Biology
Jahabarali
Unit 5 Modul
e 3 Tr
ansi
t
ion
element
s
Stability constant (Kstab) of a complex ion is the equilibrium constant for the formation of a complex ion in a
solution, from its constituent ions. It indicates the position of the equilibrium lies to the right, with a high
stability constant forming a more stable complex ion.…read more

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Sameer Biology
Jahabarali
Unit 5 Modul
e 3 Tr
ansi
t
ion
element
s
Cr2O72- 2Cr3+ Cr2O72- + 14H++ 6e¯ 2Cr3+ + 7H2O Cr2O72- + 14H+ +6Fe2+ 2Cr3+ + 6Fe2+ +
7H2O
Cr: 6+ 3+
Fe2+ Fe3+ + e¯
I¯ ½ I2 Cr2O72- + 14H++ 6e¯ 2Cr3+ + 7H2O Cr2O72- + 14H++ 6I- 2Cr3+ + 3I2 + 7H2O
I: 1- 0
I¯ ½ I2 + e¯
MnO4- Mn2+ MnO4¯ + 5e¯+ 8H+ Mn2+ + 4H2O 2MnO4¯ + 5C2O42- + 16H+ 2Mn2+ +
10CO2 + 8H2O…read more

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