Topic 13: Periodicity (HL only)

What is the overall charge, x, on the cobalt (II) complex ion: [CoCl₄]^x?

• 2+

• 2-

• 0 (no charge

• +2

Answer explanation

Which of these statements is/are correct?

1: Ligands are Lewis bases

2: Zinc compounds are colored

3: Titanium (II) compounds are paramagnetic

• 1 and 3 only

• 2 and 3 only

• 1 only

• 1 and 2 only

Answer explanation

What is the effect on d-orbital splitting and wavelength of light absorbed of a stronger ligand in an octahedral transition metal complex ion?

• d-orbital splitting decreases and wavelength decreases

• d-orbital splitting increases and wavelength increases

• d-orbital splitting decreases and wavelength increases

• d-orbital splitting increases and wavelength decreases

Answer explanation

Which of these statements about copper (I) (Cu⁺) and copper (II) (Cu²⁺) compounds is correct?

• Copper (I) compounds are diamagnetic and copper (II) compounds are paramagnetic

• Copper (I) compounds are paramagnetic and copper (II) compounds are diamagnetic

• Both copper (I) compounds and copper (II) compounds are paramagnetic

• Both copper (I) compounds and copper (II) compounds are diamagnetic

Answer explanation

Which contributes to color in transition metal complexes?

1: The splitting of the d-orbitals in energy.

2: The d-orbitals are partially filled with electrons.

3: Light is emitted when electrons fall between split d-orbitals.

• 2 and 3 only

• 1, 2 and 3

• 1 and 2 only

• 1 and 3 only

Answer explanation

What is the oxidation state of the iron, and the overall charge on the complex ion, in the compound [Fe(H₂O)₄(OH)₂]NO₃?

• Oxidation state +2; charge on the complex ion 0 (no charge)

• Oxidation state +3; charge on the complex. ion 1+

• Oxidation state +3; charge on the complex ion 0 (no charge)

• Oxidation state +4; charge on the complex ion 2+

Answer explanation

Which color of an octahedral cobalt (III) complex ion has the greatest d-orbital splitting?

• Violet

• Green

• Orange

• Blue

Answer explanation

Part of the spectrochemical series is shown below:

Br^- < F^- < H₂O < CN^-

Which statement can be correctly deduced from the series?

• Br^- is a stronger ligand than F^-

• A complex with H₂O ligands is blue

• CN^- ligands cause complexes to be violet

• CN^- ligands cause greater d-orbital splitting than H₂O

Answer explanation

Comparing [CuCl₄]^2- and [Cu(H₂O)₆]²⁺, which of these statements is/are correct?

1: [CuCl₄]^2- has greater d-orbital splitting because of the lower oxidation state of the copper

2: Both complexes are octahedral

3: The copper ion has electron configuration of [Ar]3d⁹ in both complexes

• 3 only

• 2 and 3 only

• 1 and 3 only

• 1 only

Answer explanation

What is the coordination number and oxidation state of the iron ion in [Fe(CN)₆]^3-?

• Coordination number 3; oxidation state +3

• Coordination number 3; oxidation state -3

• Coordination number 6; oxidation state -3

• Coordination number 6; oxidation state +3

Answer explanation