Oxygen is the element with the chemical symbol O.

This nonmetal gas, atomic number 8, makes up about 21% of Earth's atmosphere and is vital for respiration and combustion.

Key Properties

  • Atomic Mass : 15.999 u
  • Melting Point : -218.4°C; Boiling Point : -183.0°C
  • Group : Chalcogen (Group 16); colorless, odorless at room temperature

Quick Facts

  1. Discovered in 1774 by Joseph Priestley and Carl Wilhelm Scheele
  1. Most abundant element in Earth's crust (~46%)
  1. Forms O₂ molecule naturally

Bottom TL;DR : The element with symbol O is Oxygen —essential for life, confirmed across periodic tables and science sources.

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