--%>
Assignment Help - homework help

Explanation of oxygen family.

Group 16 of periodic table contains five elements namely, oxygen (O), sulphur (S), selenium (Se), tellurium (Te) and polonium (Po). These are collectively known as chalcogens or ore forming elements because many metal ores occur as oxides and sulphides. These elements belong to p-block. The first four members of group 16 are non-metals. Polonium has metallic character and is a radioactive element with a very short period.

Oxygen, the most abundant element, is a vital element of atmosphere and ocean. It composes 46.6% of earth's crust. It forms about 21% of air as the free element and 89% of the ocean by weight. Sulphur is less abundant and occurs about 0.052% of the earth's crust. Sulphur is also referred as Brim stone. The name sulphur is derived from Sanskrit word 'Sulveri' which means 'killer of copper'. Compared to oxygen and sulphur the other members of this group are rare.

Atoms of these elements have outer electronic configuration as ns2np4, where n varies from 2 to 6. The electronic configurations of the elements of group 16 are shown in the table below:

Elements

At. No.

Electronic configuration

Abundance in earth's crust (ppm)

Oxygen (O)

8

[He] 2s2 2p4

4.66 × 105

Sulphur (S)

16

[Ne] 3s2 3p4

5.20 × 102

Selenium (Se)

34

[Ar] 3d10 4s2 4p4

9.0 × 10-2

Tellurium (Te)

52

[Kr] 4d10 5s2 5p4

2 × 10-3

Polonium (Po)

84

[Xe] 4f14 5d10 6s2 6p4

-


The four p-electrons of the outermost shell are arranged as px2 py1 pz1. Thus, there are two half-filled p-orbitals which are used for bonding with other elements. From the similar outer electronic configuration of these elements, it is expected that they will show similar physical and chemical properties.

Oxygen the first member of this group has very high ionization energy (1314 kJ mol-1) and differs markedly from other members of the family.

Oxygen, on the other hand, is found to exhibit remarkable resemblance with its neighbours, nitrogen and fluorine. For example, it forms strong pπ-pπ bond like nitrogen. Also it forms hydrogen bonds like nitrogen and fluorine.

   Related Questions in Chemistry

  • Q : Why aryl halides are less reactive?

    Aryl halides are much less reactive towards nucleophilic substitution reactions than haloalkanes. The less reactivity of aryl halides can be described

    		•
  • Q : Molarity of Nacl solution When 5.85 g

    When 5.85 g of NaCl (having molecular weight 58.5) is dissolved in water and the solution is prepared to 0.5 litres, the molarity of the solution is: (i) 0.2 (ii) 0.4 (iii) 1.0 (iv) 0.1

    		•
  • Q : Cations Chromium(III) hydroxide is

    Chromium(III) hydroxide is highly insoluble in distilled water but dissolves readily in either acidic or basic solution. Briefly explain why the compound can dissolve in acidic or in basic but not in neutral solution. Write appropriate equations to support your answer

    		•
  • Q : Partial vapour pressure of volatile

    Choose the right answer from following. For a solution of volatile liquids the partial vapour pressure of each component in solution is directly proportional to: (a) Molarity (b) Mole fraction (c) Molality (d) Normality

    		•
  • Q : Problem on partial pressure i) Show

    i) Show that the equilibrium constant Kp for the reaction CaCo3(s) ↔ CaO(s) +CO2(g)is about unity (i.e. = 1.0) at 895 °C.ii) If two grams of calcium carbonate are pl

    		•
  • Q : Chemists have not created a periodic

    Explain the reason behind that the chemists have not created a periodic table of compounds?

    		•
  • Q : Problem on Osmotic Pressure of solution

    The osmotic pressure of a 5% solution of cane sugar at 150oC  is (mol. wt. of cane sugar = 342)(a) 4 atm (b) 3.4 atm (c) 5.07 atm (d) 2.45 atmAnswer: (c) Π = (5 x 0.0821 x 1000 x 423)/(342 x 100) = 5.07 atm

    		•
  • Q : Problem on physical and thermodynamic

    The shells of marine organisms contain calcium carbonate CaCO3, largely in a crystalline form known as calcite. There is a second crystalline form of calcium carbonate known as aragonite. Physical and thermodynamic properties of calcite and aragonite at 298

    		•
  • Q : Question relatede to calculate molarity

    Select the right answer of the question. What is molarity of a solution of HCl that contains 49% by weight of solute and whose specific gravity is 1.41 : (a) 15.25 (b) 16.75 (c) 18.92 (d) 20.08

    		•
  • Q : Volumes of solution after concentration

    Hydrochloric acid solution A and B encompass concentration of 0.5N and 0.1N  corresspondingly. The volumes of solutions A and B needed to make 2liters of 0.2N of HCL are: (i) 0.5l of A + 1.5l of B (ii) 1.5l of A + 0.5 l of B  (iii) 1.0 l of A + 1.0l of B&nbs

    		•