Target: 10 Questions in 10 minutes

An IB Chemistry data booklet is helpful
1. Which of the following is NOT a characteristic property of transition elements?
  • A.  Variable oxidation states
  • B.  Have low melting points
  • C.  Form coloured compounds
  • D.  Act as catalysts
2. What is the oxidation state of Co in the complex ion [Co(NH3)2Cl4] - ?
  • A.   -1
  • B.   +1
  • C.   +3
  • D.   +7
3. What is the charge on the complex ion [Mn(H2O)5OH] when the oxidation state for Mn is +3?
  • A.   2+
  • B.   3+
  • C.   5+
  • D.   7+

4. Which of the following statements is correct about the formation of a complex ion?

I. A complex ion consists of a metal ion surrounded by ligands.
II. A ligand is always negatively charged.
III. Coordination bonds are formed when the transition element ion donates a lone pair of electrons to the ligand.
  • A.   I only
  • B.   I and II only
  • C.   II and III only
  • D.   I, II and III
5. How many of these species, V, Cr3+, Mn2+, and Fe3+ has/ have the electronic configuration of 1s22s22p63s23p63d5?
  • A.   1
  • B.   2
  • C.   3
  • D.   4
6. Which of the following statements is correct about the change VO3- → VO2+ ?
  • A.   There is no change in the oxidation state of vanadium.
  • B.   An oxidising agent is required for this reaction.
  • C.   The oxidation state of vanadium in VO2+ is +4.
  • D.  This is a reduction reaction.
7. Which of the following salts will not form a coloured solution when dissolved in water?
  • A.   Ni(II) chloride
  • B.   Copper(II) nitrate
  • C.   Potassium dichromate (VI)
  • D.   Scandium(III) sulphate
8. Select the correct explanation for the colours of transition element compounds.
  • A.   Light is emitted when electrons fall from higher energy level to lower energy level.
  • B.   Light is absorbed when electrons are promoted from lower energy level to higher energy level.
  • C.   The colour shown by the compound is the colour absorbed by the compounds.
  • D.   The colour depends on the identity of the transition element and its charge only.

9. CrO42- ions are yellow and Cr2O72- ions are orange in colour in aqueous solutions.
For the equilibrium between this pair of ions in the equation below, which of the following statements is/are correct?

2CrO42-(aq)  + 2H+(aq)  ⇌  Cr2O72-(aq)  + H2O(l)
yellow    orange  


I. The solution becomes more orange when some acid is added
II. The forward reaction is a reduction
III. The reverse reaction is favoured by adding some alkali into the reaction mixture
  • A.   I and II only
  • B.   I and III only
  • C.   II and III only
  • D.   I, II and III
10. TiO2 is commonly used as a white paint. The reason for the absence of colour is ...
  • A.   Ti is not a transition element
  • B.   Ti is not a d-block element
  • C.   Ti4+ has an empty d-subshell
  • D.   TiO2 absorbs all the colours of the visible light