Explain oxygen and its preparation.

Karl Scheele, the Swedish chemist, was the first to prepare oxygen by heating mercuric oxide in 1772. He recognized the gas as one of the major constituents of atmospheric air and called it 'fire air'. Joseph Priestley, the English chemist also prepared oxygen by focusing the sun rays by means of a double lens on mercuric oxide. Priestley published his results in 1774 and has been regarded as the discoverer of oxygen. However, its elemental nature was proved by Lavoisier.

Oxygen is first element of group 16 of periodic table. It may be called the head of chalcogens family. Its configuration (1s22s22p4)shows the presence of six electrons in the valence shell. It does show some characteristics which are not shown by other members of the family because of its small size. For example, it is able to form pπ-pπ bonding and exists as diatomic molecule (O2). The other elements of the group do not exist as diatomic molecule due to their inability to form pπ-pπ bonding.

Isotopes of oxygen

Oxygen has three naturally occurring isotopes which are:


Out of these three isotopes, O-18 is radioactive in nature and finds frequent use in studying the mechanisms of organic reactions and other trace techniques. Like hydrogen, oxygen also exists in the elementary form as diatomic molecule (O2) and is referred to as dioxygen. 

Terrestrial abundance and distribution

Oxygen is the most abundant element on the surface of the earth. In Free State, it occurs in air and constitutes 21% by volume of air and 23% by weight. In the combined state, it constitutes 89% by mass of water and 50% by mass of earth's solid crust. In earth's solid crust, it is mainly present as silicates, carbonates, aluminates and oxides of metals.

Almost all the dioxygen in atmosphere is believed to be the result of photosynthesis by green plants which can be represented as 


   Related Questions in Chemistry

  • Q : Determining concentration in ppm A 500

    A 500 gm tooth paste sample has 0.2g fluoride concentration. Determine the concentration of F in terms of ppm level: (a) 250 (b) 200 (c) 400 (d) 1000Answer: (c) F-ions in ppm = (0.2/500) x 106 = 400

  • Q : Describe Transformation Matrices. Each

    Each symmetry operation can be represented by a transformation matrix.You have seen what happens when a molecule is subjected to the symmetry operation that corresponds to any of the symmetry elements of the point group to which the molecule belongs. The m

  • Q : The Liver Is Responsible For Much Of

    The Liver Is Responsible For Much Of The Pentose Phosphate Activity Explain

  • Q : Solutions The normality of 10 lit.

    The normality of 10 lit. volume hydrogen peroxide is: (a) 0.176 (b) 3.52 (c) 1.78 (d) 0.88 (e)17.8

  • Q : Whether HCl is a base or an acid

    Whether HCl is a base or an acid? Briefly state your comments?

  • Q : Molar mass what is the equation for

    what is the equation for calculating molar mass of non volatile solute

  • Q : Vapour pressure of water Give me answer

    Give me answer of this question. 5cm3 of acetone is added to 100cm3 of water, the vapour pressure of water over the solution: (a) It will be equal to the vapour pressure of pure water (b) It will be less than the vapour pressure of pure water

  • Q : Preparation of normal solution Give me

    Give me answer of this question. What weight of ferrous ammonium sulphate is requiored to prepare 100 ml of 0.1 normal solution (mol. wt. 392): (a) 39.2 gm (b) 3.92 gm (c)1.96 gm (d)19.6 gm

  • Q : Mole fraction of solute The mole

    The mole fraction of the solute in 1 molal aqueous solution is: (a) 0.027 (b) 0.036 (c) 0.018 (d) 0.009What is the correct answer.

  • Q : P block why BiF3 is ionic whereas other

    why BiF3 is ionic whereas other trihalides are covalent in nature?

©TutorsGlobe All rights reserved 2022-2023.