3.4 Chemistry of the d-block transition metals Flashcards
What is a transition metal?
A transition metal is a d-block element that forms one or more stable ions with partially filled d-orbitals.
Which two elements in the d-block of the periodic table are not technically transition metals?
Scandium and zinc.
They do not form ions with an incomplete d-subshell.
Which two elements in the periodic table are exceptions to the rule that the 4s orbital is filled before the 3p orbital?
Chromium and copper. The 4s orbital only fills the one electron as this gives them more stable configurations in the 3d orbital.
Chromium: [Ar] 4s1 3d5
Copper: [Ar] 4s1 3d10
What are some general properties of transition metals?
- They have variable oxidation states.
- They form complex ions.
- They form coloured ions in solution.
- They can catalyse reactions either as elements or in compounds.
Give examples of transition metals that have variable oxidation states
Fe2+ and Fe3+
Cu+ and Cu2+
Cr2+ and Cr3+
Why do transition metals have variable oxidation states?
Variable oxidation states arise because the electrons in the 4s and 3d orbitals have very similar energies. This means that a relatively similar amount of energy is required to gain or lose different numbers of electrons.
What are the most common oxidation states of Cr?
+2
+3
+6
What are the most common oxidation states of Mn?
+2
+4
+7
What are the most common oxidation states of Fe?
+2
+3
What are the most common oxidation states of Cu?
+1
+2
What are the most common oxidation states of Co?
+2
+3
What colour are aqueous solutions of compounds containing Cr3+ ions?
Green
What colour are aqueous solutions of compounds containing CrO4^2- ions?
Yellow
What colour are aqueous solutions of compounds containing Cr2O7^2- ions?
Orange
What colour are aqueous solutions of compounds containing MnO4^- ions?
Purple
What colour are aqueous solutions of compounds containing Co2+ ions?
Pink
What colour are aqueous solutions of compounds containing Fe2+ ions?
Green
What colour are aqueous solutions of compounds containing Fe3+ ions?
Brown
What colour are aqueous solutions of compounds containing Cu2+ ions?
Blue
What is a ligand?
A ligand is an ion or molecule that bonds to a central metal atom to form a complex ion.
What type of bonding is involved in the formation of metal complex ions?
Coordinate bonding
What is a complex ion?
A complex ion is a central metal ion surrounded by ligands
Aqueous solutions of transition metal ions are usually ______ .
Fill in the gap
Coloured
What is meant by coordination number?
The number of dative bonds formed with a central metal ion.