A technician prepares magnesium oxide for a ceramic coating. Fig. 1 is a diagram of a magnesium atom and an oxygen atom before the reaction. Magnesium is a ...
Question 1 Report
A technician prepares magnesium oxide for a ceramic coating. Fig. 1 is a diagram of a magnesium atom and an oxygen atom before the reaction. Magnesium is a solid metal, while oxygen is a gas. The oxide is made by heating magnesium in air.
(a) Complete the electronic configuration of magnesium shown by the diagram: 2, 8, ... [2]
(b) Name the group containing magnesium. [1]
(c) Give the number of electrons in the outer shell of an oxygen atom. [1]
(d) Explain how magnesium oxide contains Mg2+ and O2− ions. [4]
(e) Write the balanced symbol equation for the reaction between magnesium and oxygen. [3]
(f) State two observations when magnesium burns in oxygen. [2]
(g) Give one reason why magnesium oxide is not described as an element. [2]
Answer Details
(a) Magnesium has two electrons in its third shell. The completed configuration is \(2,8,2\). Award 1 mark for the final 2 and 1 mark for the full configuration. [2]
(b) Magnesium is in group 2. [1]
(c) Oxygen has 6 electrons in its outer shell. [1]
(d) Magnesium loses two electrons [1] to form \(\mathrm{Mg^{2+}}\). [1] Oxygen gains two electrons [1] to form \(\mathrm{O^{2-}}\), so both obtain full outer shells. [1] [4]
(e) The balanced equation is:
\[\mathrm{2Mg+O_2\rightarrow2MgO}\]
Correct balancing gives 2Mg, \(\mathrm{O_2}\), and 2MgO. [3]
(f) Magnesium burns with a bright white flame or light [1] and forms a white solid or powder. [1] [2]
(g) Magnesium oxide is not an element because it contains two different elements, magnesium and oxygen, [1] chemically combined in \(\mathrm{MgO}\). [1] [2]
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