Orbitals and electronic configurationEdexcel International A Level Chemistry: Subtopic test

1. 1
   A student is learning to write the electronic configurations of atoms and ions of elements in the first four periods.

   (a)

   What is the maximum number of electrons that can occupy the 3d sub-shell?

   [1 mark]

   • A2
   • B6
   • C14
   • D10

   (b)

   Which statement describes the shape of a 2p orbital?

   [1 mark]

   • ASpherical
   • BDumbbell-shaped, with two lobes along an axis
   • CTetrahedral
   • DRing-shaped around the nucleus

   (c)

   State what is meant by the term orbital.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Iron (atomic number 26) is the most widely used transition metal. Iron(II) and iron(III) ions are found in haemoglobin and in rust.

   (a)

   What is the electronic configuration of the Fe²⁺ ion?

   [1 mark]

   • A1s²2s²2p⁶3s²3p⁶3d⁴4s²
   • B1s²2s²2p⁶3s²3p⁶3d⁵4s¹
   • C1s²2s²2p⁶3s²3p⁶3d⁶
   • D1s²2s²2p⁶3s²3p⁶3d⁶4s²

   (b)

   How many unpaired electrons are there in an Fe³⁺ ion?

   [1 mark]

   • A5
   • B4
   • C3
   • D6

   (c)

   Describe how the six 3d electrons of an Fe²⁺ ion are arranged in the 3d orbitals, and explain why they are arranged in this way.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A transition metal course covers elements from scandium to zinc. The atomic numbers are: vanadium 23, manganese 25 and zinc 30.

   (a)

   Write the full electronic configuration, using s, p, d notation, of (i) a vanadium atom, (ii) a V³⁺ ion and (iii) a Zn²⁺ ion.

   [3 marks]

   (b)

   Deduce the number of unpaired electrons in a manganese atom and in a Mn²⁺ ion. Describe the arrangement of the electrons in the 3d and 4s orbitals.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A chemistry department compares four elements in the Periodic Table: nitrogen (atomic number 7), neon (10), sodium (11) and chlorine (17).

   (a)

   Describe the s and p orbitals and the way electrons occupy them in an atom of nitrogen.

   [6 marks]

   (b)

   Explain, in terms of electronic configuration, why neon is unreactive, why sodium forms Na⁺ ions and why chlorine forms Cl⁻ ions.

   [6 marks]

   Total for question 4: 12 marks

End of questions