What is the Difference Between Atomic Oxygen and Molecular Oxygen?

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The main difference between atomic oxygen and molecular oxygen lies in their structure and reactivity. Here are the key differences:

  • Atomic Oxygen:
  • Consists of a single oxygen atom represented by the symbol O.
  • Has 8 protons, 8 electrons, and usually 8 neutrons.
  • Highly reactive due to its unpaired electron.
  • Can be produced in the gas phase at high temperatures in laboratory settings.
  • Not normally observed in nature, as oxygen typically exists as molecular oxygen.
  • Molecular Oxygen:
  • Composed of two oxygen atoms connected to each other by covalent bonds, forming a diatomic molecule represented by the symbol O2.
  • The two oxygen atoms have a total of 16 electrons, with each atom having a full octet of electrons.
  • Less reactive than atomic oxygen, as the two oxygen atoms share electrons and have a stable configuration.
  • Exists as a colorless gas in the atmosphere, making up approximately 21% of the Earth's atmosphere.
  • Essential for respiration in organisms and is the form of oxygen we breathe.

In summary, atomic oxygen is a highly reactive single oxygen atom, while molecular oxygen is a less reactive diatomic molecule consisting of two oxygen atoms bonded together. Molecular oxygen is the predominant form of oxygen found in nature and is essential for life on Earth.

Comparative Table: Atomic Oxygen vs Molecular Oxygen

Here is a table summarizing the differences between atomic oxygen and molecular oxygen:

Property Atomic Oxygen Molecular Oxygen
Symbol O(3P) O2
Reactivity Highly reactive Less reactive
Structure Free radical Diatomic molecule
Occurrence Rarely found naturally, predominant in outer space Present in Earth's atmosphere (about 21%)
Bonding No covalent bonds Two covalent bonds between two oxygen atoms
Molar Mass 16 g/mol (15.9994 to be precise) 32 g/mol

Atomic oxygen is a highly reactive free radical with the symbol O(3P), while molecular oxygen is a diatomic molecule with the symbol O2. Atomic oxygen does not exist naturally for even a short period, but it is the predominant form of oxygen in outer space. In contrast, molecular oxygen is present in Earth's atmosphere and is essential for organisms' respiration. The molar mass of atomic oxygen is 16 g/mol, while the molar mass of molecular oxygen is 32 g/mol.