--%>
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 : Explain equilibrium and molecular

    The equilibrium constant can be treated as a particular type of molecular distribution. Consider the simplest gas-phase reaction, one in which molecules of A are converted to molecules of B. the reaction, described by the equation

    Q : Unit of molality Select the right

    Select the right answer of the question. The unit of molality is: (a) Mole per litre (b) Mole per kilogram (c) Per mole per litre (d) Mole litre

    		•
  • Q : Problem on endothermic or exothermic At

    At low temperatures, mixtures of water and methane can form a hydrate (i.e. a solid containing trapped methane). Hydrates are potentially a very large source of underground trapped methane in the pole regions but are a nuisance when they form in pipelines and block th

    		•
  • Q : Liquid Vapour Free Energies The free

    The free energy of a component of a liquid solution is equal to its free energy in the equilibrium vapour.Partial molal free energies let us deal with the free energy of the components of a solution. We use these free energies, or simpler concentration ter

    		•
  • Q : Calculating number of moles from

    Choose the right answer from following. If 0.50 mol of CaCl2 is mixed with 0.20 mol of Na3PO4, the maximum number of moles of Ca3 (PO2)2 which can be formed: (a) 0.70 (b) 0.50 (c) 0.20 (d) 0.10

    		•
  • Q : Reason for medications contain hcl What

    What is the reason behind this that some medications contain hcl?

    		•
  • Q : How haloalkanes are prepared from

    This is the common method for preparing haloalkanes in laboratory. Alcohols can be converted to haloalkanes by substitution of - OH group with a halogen atom. Different reagents can be used to get haloa

    		•
  • Q : Problem on making solution Select the

    Select the right answer of the question. The weight of H2C2O42H2O required to prepare 500ml of 0.2N solution is : (a) 126g (b) 12.6g (c) 63g (d) 6.3g

    		•
  • Q : Basic concepts Determination of correct

    Determination of correct mol. Mass from Roult's law is applicable to :

    		•
  • Q : Depression in the freezing point When

    When 0.01 mole of sugar is dissolved in 100g of a solvent, the depression in freezing point is 0.40o. When 0.03 mole of glucose is dissolved in 50g of the same solvent, depression in the freezing point will be:(a) 0.60o  (b) 0.80o

    		•