Electronic configuration and orbitalsEdexcel A-Level Chemistry: Subtopic test

1. 1
   A student is revising the electronic configurations of atoms and ions of elements up to atomic number 36, using the periodic table to help her.

   (a)

   Which is the electronic configuration of a sulfide ion, S²⁻ (Z = 16)?

   [1 mark]

   • A1s²2s²2p⁶3s²3p⁶
   • B1s²2s²2p⁶3s²3p⁴
   • C1s²2s²2p⁶3s²3p²
   • D1s²2s²2p⁶3s²

   (b)

   Which element is in the p block of the periodic table?

   [1 mark]

   • ACalcium
   • BIron
   • CAluminium
   • DScandium

   (c)

   Write the electronic configuration of an iron atom (Z = 26) in 1s notation and deduce the number of unpaired electrons it contains.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   The first ionisation energies of four successive elements, in kJ mol⁻¹, are: lithium 520, beryllium 900, boron 801 and carbon 1086.

   (a)

   The fall in first ionisation energy from beryllium to boron is evidence for which of the following?

   [1 mark]

   • AThe existence of isotopes of boron
   • BThe existence of sub-shells within a shell
   • CThe relative atomic mass of boron
   • DThe nuclear charge decreasing from beryllium to boron

   (b)

   What is the maximum number of electrons that can fill the third quantum shell (n = 3)?

   [1 mark]

   • A8
   • B10
   • C32
   • D18

   (c)

   Explain why the first ionisation energy of boron is lower than that of beryllium.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Nitrogen has atomic number 7. Its atoms have electrons in s and p orbitals.

   (a)

   Describe the shape of an s orbital and the shape of a p orbital, and state how many electrons an orbital can hold.

   [3 marks]

   (b)

   Describe how the seven electrons of a nitrogen atom are arranged in an electrons-in-boxes diagram, explaining the arrangement of the 2p electrons.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Potassium (Z = 19) reacts with bromine (Z = 35) to form potassium bromide. The successive ionisation energies of potassium, in kJ mol⁻¹, are: 1st 419, 2nd 3052, 3rd 4420, 4th 5877, 5th 7975, 6th 9590, 7th 11343, 8th 14944, 9th 16963 and 10th 48610.

   (a)

   Explain how the successive ionisation energies of potassium provide evidence for the arrangement of electrons in quantum shells, and write the electronic configuration of a potassium atom.

   [6 marks]

   (b)

   Explain how the electronic configurations of potassium and bromine determine the formation of potassium bromide and the block of the periodic table to which each element belongs.

   [6 marks]

   Total for question 4: 12 marks

End of questions