Question

Fill in the blanks by selecting a correct word/terms given in the brackets.

When magnesium is burnt in oxygen ___ compound is formed. (covalent/ionic)

Answer 1

1. The burning of magnesium $\left(\mathrm{Mg}\right)$ in air produces Magnesium oxide $\left(\mathrm{MgO}\right)$. The balanced equation for the reaction is:$$\begin{gathered} 2\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{MgO}\left(\mathrm{s}\right) \\ \left(\mathrm{Magnesium}\right)\left(\mathrm{Oxygen}\right)(\mathrm{Magnesium}\mathrm{oxide}) \end{gathered}$$
2. Magnesium is a metal with an electronic configuration of $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^2$. Therefore, the valence shell has 2 electrons which are removed to attain a stable electronic configuration. Magnesium forms a divalent cation. Oxygen is a non-metal with an electronic configuration of $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^4$. It has 6 electrons in the valence shell and therefore accepts 2 electrons to attain a stable configuration.
3. Therefore, the electrons removed from magnesium are accepted by oxygen to form a divalent anion. The cation from magnesium and anion from oxygen are held together to form Magnesium oxide with an ionic bond between them.
   Therefore, when magnesium is burnt in oxygen, an ionic compound is formed.