Chemistry - Oxygen

Introduction

• Oxygen is the member of group 16 on the periodic table; however, most of the time, it is treated differently from its group.

• The symbol of oxygen is ‘O’ and atomic number is ‘8.’

• Oxygen has about nine allotropes and the most common allotrope is diatomic oxygen (i.e. O₂). Other important allotrope is Ozone i.e. O₃.

• Oxygen, first time, was noticed by Swedish pharmacist Carl Wilhelm Scheele.

Salient Features of Oxygen

• Oxygen is characteristically categorized as the member of “chalcogen” group.

• The word "chalcogen" is derived from a Greek word “khalkόs,” which means “copper” and the Latin-Greek word “Genēs,” which means born or produced.

• Oxygen is a highly reactive gas (or nonmetallic element); hence, it is an oxidizing agent that readily forms oxides with most of the elements and compounds.

• Oxygen has six valence electrons.

• The melting point of oxygen is -218.8⁰C and the boiling point is -183⁰C.

Occurrence of Oxygen

• With about 20.8 percent share (in total earth’s atmospheric constituents), oxygen is the second ranked element of the earth’s atmosphere.

• Oxygen occurs almost in sphere of the earth namely atmosphere, hydrosphere, and lithosphere.

• During the photosynthesis process, free oxygen is produced by all green plants.

• Oxygen occurs as constituent copper ores.

• A human body contains about 65 percent oxygen.

• By mass, almost half of the earth’s crust is composed of oxygen (i.e. its oxides).

• By mass, oxygen is the third-most abundant element that found in the universe; the first and second are hydrogen and helium accordingly.

• Oxygen (i.e. O₂) is a colorless and odorless diatomic gas.

• Oxygen dissolves in water very easily; however, the solubility of oxygen in the water is temperature-dependent.

Compounds of Oxygen

• Following are the major compounds of oxygen −

  • Oxide

  • Peroxide

  • Carbon dioxide - CO₂

  • Hydroxide - OH^-

  • Ozone - O₃

  • Mercury (II) oxide - HgO

  • Chlorate - ClO₃

  • Aluminum oxide - Al₂O₃

  • Carbon monoxide - CO

  • Hypochlorite - ClO^-

  • Silicon dioxide - SiO₂

  • Hypofluorous acid - HOF

  • Sodium peroxide - Na₂O₂

  • Potassium chlorate - KClO₃

  • Oxygen difluoride - OF₂

  • Sodium oxide - Na₂O

Uses of Oxygen

• Oxygen (O₂) is the most essential requirements for the respiration, without it, life cannot be imagined.

• Oxygen is used in medicine.

• Oxygen therapy is typically used to treat some diseases, such as, emphysema, pneumonia, some heart disorders, etc.

• Some of the underwater activities, such as scuba diving, submarines, etc. also use artificial oxygen.

• Aircrafts, mountaineers, etc. also use artificial oxygen.

• Oxygen is also used in some of the industries, e.g. smelting of iron ore into steel – in this process, about 55% of oxygen is used.