Types of Oxides (Amphoteric/Neutral)

This lesson covers: 

  1. How to categorise oxides as acidic, basic, or amphoteric
  2. The factors that determine if an oxide will be acidic, basic, or amphoteric
  3. Examples of acidic, basic, and amphoteric oxides

Acidic oxides & basic oxides

Periodic table highlighting metals forming basic oxides and non-metals forming acidic oxides.

Oxides, compounds containing oxygen and another element, are often classified based on their reactions:

Acidic oxides - react with bases to produce salts and water. They are typically formed by non-metals, which are located on the right side of the periodic table.

Examples of acidic oxides
CO2_2
NO2_2
SO3_3

Basic oxides - react with acids to also form salts and water. These oxides usually come from metals found on the left side of the periodic table.

Examples of basic oxides
Na2_2O
CaO
CuO

Amphoteric oxide properties


Amphoteric oxides exhibit both acidic and basic properties:

  • Amphoteric oxides can react with both acids and bases, forming salts and water in each reaction.
  • They are generally formed by elements situated near the metal-nonmetal border on the periodic table.


Example: Reactions involving amphoteric aluminium oxide

Aluminium oxide (Al2O3) can react with both acids and bases.

  1. It acts like a base when reacting with an acid (hydrochloric acid):
  • Al2O3 + 6HCl → 2AlCl3 + 3H2O
  1. It acts like an acid when reacting with a base (sodium hydroxide):
  • Al2O3 + 2NaOH → 2NaAlO2 + H2O


Other notable amphoteric oxides include zinc oxide (ZnO) and lead(II) oxide (PbO).

Which type of oxide reacts with bases to produce salts and water?

Amphoteric oxides

Acidic oxides

Basic oxides

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Which of the following is an example of an acidic oxide?

Na2O (sodium oxide)

Al2O3 (aluminium oxide)

CO2 (carbon dioxide)

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Which type of oxide is typically formed by non-metals?

Amphoteric oxides

Basic oxides

Acidic oxides

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Which of the following is an example of a basic oxide?

Na2O (sodium oxide)

Al2O3 (aluminium oxide)

CO2 (carbon dioxide)

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Which type of oxide can react with both acids and bases?

Basic oxides

Acidic oxides

Amphoteric oxides

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