Question

1. using lewis dot diagrams, show how sodium and oxygen react to form sodium oxide. what is the formula of this compound? 3 marks

Explanation:

Step1: Determine the valence electrons

Sodium (Na) has 1 valence electron ($Na\cdot$). Oxygen (O) has 6 valence electrons ($\cdot\!\!\!\cdot\!\!\!O\!\!\cdot\!\!\!\cdot$).

Step2: Electron transfer

Each Na atom donates 1 electron. Oxygen needs 2 electrons to complete its octet. So 2 Na atoms donate electrons to 1 O atom.
The Lewis dot diagram for the reaction:

$$2Na\cdot+\cdot\!\!\!\cdot\!\!\!O\!\!\cdot\!\!\!\cdot ightarrow Na^{+}[:\!\!\cdot\!\!\cdot\!\!\!O\!\!\cdot\!\!\cdot\!\!\! :]^{2 -}Na^{+}$$

Step3: Write the formula

Since there are 2 $Na^{+}$ ions and 1 $O^{2 -}$ ion, the formula of sodium oxide is $Na_{2}O$.

Answer:

The formula of sodium oxide is $Na_{2}O$.