Long Answer TypeOn the basis of VSEPR theory, predict the shapes of given molecules: PCl5 and SF6.
(i) PCl5 molecule. The electronic configuration of central phosphorus atom is
It has five valence electrons. All the five electrons are mutually shared with the electrons of five chlorine atoms to form five P - Cl bonds as shown.
Hence, P atom is surrounded by five shared pairs of electrons. These repel each other and take up such positions and there is no further repulsion between them. The most favourable arrangement is trigonal bipyramidal.
(ii) SF6 molecule: The electronic configuration of central sulphur atom is
It has six valence electrons.
All the six valence electrons are mutually shared by the electrons of six fluorine atoms to form six S – F bonds.
Hence, S atom is surrounded by six shared pairs of electrons (six bond pairs). These repel each other and try to remain as far apart as possible so that there is no further repulsion between them. Under such conditions, the most favourable arrangement is octahedral.
Discuss the shape of the following molecules using VSEPR model:
BeCl2, BCl3, SiCl4, AsF5, H2S, PH3
Short Answer TypeLong Answer TypeDiscuss in brief sp2 hybridization (hybridization in C = C bond). Discuss the molecular orbital structure of ethylene (first member of alkene).
Or
Draw diagrams showing the formation of a double bond between carbon atoms in C2H4.
Short Answer TypeApart from tetrahedral geometry, another possible geometry for CH4 is square planar with four H atoms at the corners of the square and the C atom at its centre. Explain why CH4 is not square planar?
Long Answer TypeShort Answer TypeThe central atoms in CH4, NH3 and H2O are all said to have similar hybridisation but the bond angle H – A – H (where A is C, N or O) is different in each case. Explain stating in which case it is maximum and in which case it is minimum.
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