Role of Chemistry in Environmental Protection and Economic Development

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Guess Paper – 2009
Class – X
Subject – Chemistry
(P- Block Elements)

Kalra sir 09460472649 kalra1977@rediffmail.com

Group 15 elements:
|Symbol |Atomic |Electronic configuration | | |number | | | |7 |[He]2s22p3 | |N | | | |P |15 |[Ne] 3s23p3 | |As |33 |[Ar]3d104s24p3 | |Sb |51 |[Kr]4d105s25p3 | |Bi |83 |[Xe]4f 145d106s26p3 |

General introduction, electronic configuration, occurrence, oxidation states, trends in physical and chemical properties; nitrogen - preparation, properties and uses; compounds of nitrogen: preparation and properties of ammonia and nitric acid, oxides of nitrogen (structure only); Phosphorous-allotropic forms; compounds .of phosphorous: preparation and properties of Phosphine, halides (PCl3, PCl5) and oxoacids (elementary idea only)

Group 16 elements:
|Symbol |Atomic |Electronic configuration | | |number | | | |8 |[He]2s22p4 | |O | | | |S |16 |[Ne] 3s23p4 | |Se |34 |[Ar]3d104s24p4 | |Te |52 |[Kr]4d105s25p4 | |Po |84 |[Xe]4f 145d106s26p4 |

General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties; Dioxygen: preparation, properties and uses; simple oxides; Ozone. Sulphur - allotropic forms; compounds of sulphur: preparation, properties and uses of Sulphurdioxide; sulphuric acid: industrial process of manufacture, properties and uses, oxoacids of Sulphur (structures only).

Group 17 elements:
|Symbol |Atomic number |Electronic configuration | |F |9 |[He]2s22p5 | |Cl |17 |[Ne] 3s23p5 | |Br |35 |[Ar]3d104s24p5 | |I |53 |[Kr]4d105s25p5 | |At |85 |[Xe]4f 145d106s26p5 |

General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties; compounds of halogens: preparation, properties and uses of chlorine and hydrochloric acid, Interhalogen compounds, oxoacids of halogens (structures only).

Group 18 elements:
|Symbol |Atomic number |Electronic configuration | |He |2 |1s2 | |Ne |10 |[He]2s22p6 | |Ar |18 |[Ne] 3s23p6 | |Kr |36 |[Ar]3d104s24p6 | |Xe |54 |[Kr]4d105s25p6 | |Rn |86 |[Xe]4f 145d106s26p6 |

General introduction, electronic configuration. Occurrence, trends in physical and chemical properties, uses.

1.Account for the following: (Group 15 elements)

(i) There is a considerable increase in covalent radius from N to P. However, from As to Bi only small increase in covalent radius is observed. Ans: This is due to the presence of completely filled d and/or f orbital in heavier members. (ii) Ionization enthalpy decreases down the group 15.

Ans: Due to gradual increase in atomic size.
(iii) The ionization enthalpy of the group 15 elements is much greater than that of group 14 elements in the corresponding periods. Ans: Because of the extra stable half-filled p orbital electronic configuration and smaller size. (iv) Nitrogen exists as diatomic molecule and phosphorus as P4. Ans: Because N2 is...
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