BRAINCAKEMelting Points of Period 3 Oxides
The melting points of the Period 3 oxides follow from their structure and bonding.
Ionic oxides (high melting points). Na2O, MgO and Al2O3 have giant ionic lattices, and melting means overcoming strong electrostatic attraction between oppositely charged ions. MgO melts higher than Na2O because Mg2+ has a higher charge (and is smaller) than Na+, so it attracts O2− ions more strongly. MgO has the highest melting point of the Period 3 oxides (about 2850 °C).
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Key terms in this lesson
- macromolecular
- Describes a giant covalent structure in which atoms are joined throughout by strong covalent bonds, such as in silicon dioxide.
- polarisation
- The distortion of the electron cloud of a negative ion caused by the attraction of a nearby positive ion, giving the bond some covalent character.
More in Period 3 Elements and Oxides
- Period 3 Elements
- Reactions of Sodium and Magnesium with Water
- Reactions of Period 3 Elements with Oxygen
- Period 3 Oxides
- Reactions of Period 3 Oxides with Water
- pH of Period 3 Oxide Solutions
- Acid-Base Character of Period 3 Oxides
- Amphoteric Aluminium Oxide
All 10 lessons in Period 3 Elements and Oxides · All AQA A-level Chemistry topics