How does the electron sea model explain the conductivity of metals? The malleability and ductility of metals?
Solution:Step-1 (a) Here the bond angles of the molecules vary in according to the presence of lone pairs electrons on the central atom. In ClO , the central atom is Cl atom and in NO , the - 2 2 central atom is N atom. 2 5 2 2 3 2 2 417l [Ne] 3s 3p 7N 1s 2s 2p 8 1s 2s 2p The Lewis structure of both the molecules areIn case of ClO there2re 2 bonded pairs atom and 2 nonbonded pairs of electrons on the centralatom . Hence its steric number will beSteric number(SN) = (number of atoms bonded to central atom) +(number of lone pair on centralatom) = 2+2=4A molecule , having steric number 4 with 2 bonded pairs and 2 nonbonded electrons on thecentral atom the electron domain geometry will be tetrahedral, molecular geometry is bentstructure with bond angle 104.5 . o -Whereas in NO 2Steric number(SN) = (number of atoms bonded to central atom) +(number of lone pair on centralatom) = 2+1=3 A molecule , having steric number 3 with 2 bonded pairs and 1 nonbonded electrons on thecentral atom the electron domain geometry will be trigonal planar and molecular geometry is obent structure with bond angle 119 .Hence the variation in bond angle is due to the presence of differnt numbers of nonbondedelectrons on the molecule. Greater the number of nonbonded electrons on the molecule more isthe repulsion between bond pairs and lone pair.Step-2(b) Linear shape of XeF molecule2Explanation Xe [Kr] 4d 5s 5p2 6 F [He] 2s 2p2 554 9\nTotal valence electrons= 8 + 2(7)=22There are 22 electrons in the molecule that are valence electrons. The 3 pairs of electrons arethere on each fluorine atom as shown in the figure, which form the octet structure along with thebonded pair between them and central Xe atom. Thus there are a total of 8 pairs. The remaining 3lone pairs on Xe atom as shown in the figure completes the 11 pairs.These are arranged in trigonal bipyramidal molecular geometry. The three non bonded pair ofelectrons prefer the equatorial position. The bonded pair of electrons take the apical position ofthe trigonal bipyramid and hence the molecule is linear.The molecule is termed as linear because the bonded pairs cannot move around the centralXenon atom but the lone pairs can move. In spectroscope these lone pairs appear like a cloud.