Problem 13 - Chemistry: The Central Science

Question

Using Lewis symbols, diagram the reaction between magnesium and oxygen atoms to give the ionic substance \(\mathrm{MgO}\).

Step-by-Step Solution

Answer

First, identify the valence electrons of Mg (2) and O (6). Draw their Lewis symbols with dots representing valence electrons. Show the transfer of two electrons from Mg to O using arrows, and draw the resulting ions with their new electron configurations as \(Mg^{2+}\) and \(O^{2-}\). Finally, write the formula for magnesium oxide as \(\mathrm{MgO}\).

Step 1: Identify the Valence Electrons

First, identify the number of valence electrons of each atom. Magnesium is in group 2 of the periodic table and has 2 valence electrons. Oxygen is in group 6 and has 6 valence electrons.

Step 2: Draw the Lewis Symbols

Draw the Lewis symbols for magnesium and oxygen. Represent each valence electron as a single dot around the atomic symbol. For magnesium (Mg), place two dots on either side of the Mg symbol. For oxygen (O), arrange the six dots in pairs around the O symbol. Mg: O: •• •• Mg O ••

Step 3: Show Electron Transfer

In the reaction, magnesium will lose two electrons to achieve a stable electron configuration, while oxygen will gain two electrons. Show this electron transfer by drawing arrows representing the transfer of the two electrons from Mg to O: Mg: O: ••→ •• Mg → O ••

Step 4: Draw the Resulting Ions

After the electron transfer, draw the resulting ions with their new electron configurations. Magnesium will have lost its two valence electrons, while oxygen will have gained two more electrons, resulting in eight electrons in its outer shell. Mg: O: (••) Mg²⁺ O²⁻ (••)

Step 5: Write the Final Formula

Write the final formula for magnesium oxide as \(\mathrm{MgO}\). The positive and negative charges of the ions cancel out, resulting in a neutral compound.