Explain why transition metals exhibit variable oxidation states in contrast to alkali metals.

Describe the bond formation when urea acts as a ligand in a transition metal complex ion.

Suggest why experiments involving tetracarbonylnickel are very hazardous.

Which is correct for the complex ion in [Fe(H₂O)₅Cl]SO₄?

State and explain the magnetic property of iron(II) and iron(III) ions.

What is the charge on the iron(III) complex ion in [Fe(OH)₂(H₂O)₄]Br?

A.     0

B.     1+

C.     2+

D.     3+

Which electrons are removed from iron (Z = 26) to form iron(II)?

A. two 3d electrons

B. two 4s electrons

C. one 4s electron and one 3d electron

D. two 4p electrons

What is the oxidation state of the metal ion and charge of the complex ion in [Co(NH₃)₄Cl₂]Cl?

Explain why iron forms many different coloured complex ions.

Describe, in terms of the electrons involved, how the bond between a ligand and a central metal ion is formed.

Formulate an equation for the oxidation of nickel(II) sulfide to nickel(II) oxide.

Mg(OH)⁺ is a complex ion, but Mg is not regarded as a transition metal. Contrast Mg with manganese, Mn, in terms of one characteristic chemical property of transition metals, other than complex ion formation.

Predict two other chemical properties you would expect rhenium to have, given its position in the periodic table.

Ammonia is a stronger ligand than water. Which is correct when concentrated aqueous ammonia solution is added to dilute aqueous copper(II) sulfate solution?

A.     The d-orbitals in the copper ion split.

B.     There is a smaller splitting of the d-orbitals.

C.     Ammonia replaces water as a ligand.

D.     The colour of the solution fades.

The nickel obtained from another ore, nickeliferous limonite, is contaminated with iron. Both nickel and iron react with carbon monoxide gas to form gaseous complexes, tetracarbonylnickel, $\text{Ni(CO}{\text{)}}_{\text{4}}\text{(g)}$, and pentacarbonyliron, $\text{Fe(CO}{\text{)}}_{\text{5}}\text{(g)}$. Suggest why the nickel can be separated from the iron successfully using carbon monoxide.

What is the overall charge, $x$, of the chromium (III) complex?

$\left[\mathrm{Cr}\right({\mathrm{H}}_2\mathrm{O}{)}_4{\mathrm{Cl}}_2{]}^x$

A.  0

B.  1+

C.  2−

D.  3+

Which complex ion contains a central ion with an oxidation state of +3?

A.  [PtCl₆]²⁻

B.  [Cu(H₂O)₄(OH)₂]

C.  [Ni(NH₃)₄(H₂O)₂]²⁺

D.  [Co(NH₃)₄Cl₂]⁺