periodic table

Question 1

Explain why the oxides of sodium and silicon have these formulae.

Answer 1

1. Na2O has giant ionic lattice.
2. To achieve stable octet configuration, Na loses 1 electron to become Na+ while O gains 2 electrons to become O2−
3. To obtain electrical neutrality, the formula is Na2O.
   +
4. SiO2 has giant molecular structure.
5. To achieve stable octet configuration, each Si atom is bonded to 4 O atoms while each O atom is bonded to 2 Si atoms.
6. Since the number of O atoms is twice that of Si, the empirical formula is SiO2.