Refer to Table 6.2. 

(a) Write an equation for the process for which the standard enthalpy of atomization of cobalt is defined. 

(b) Suggest reasons for the trend in standard enthalpies of atomization on descending group 1. 

(c) Outline possible reasons for the trend in values of ∆_aH° on going from Cs to Bi.

Table 6.2.

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Li 1 2 3 4 5 454 161 157 Na 371 108 K 337 90 235 Cs Be 301 78 1560 324 112 Mg 923 146 Rb Sr 312 1040 1799 DE 82 250 Ba Sc 1115 1814 178 378 470 197 164 147 Zr 164 423 215 182 La 178 423 188 272 224 Ti Be 1560 324 112 1941 2183 2180 514 135 Nb Hf 2128 2750 609 721 147 Ta 3290 782 619 159 147 6 7 8 9 10 11 12 13 14 397 129 Mo Metal lattice type Melting point (K) Standard enthalpy of atomization (kJ mol-¹) Metallic radius for 12-coordinate atom (pm) 2896 658 140 W Mn see text 1519 283 137 Tc 2430 677 135 Re Fe 850 774 141 1811 1768 418 428 126 125 Ru Rh 2607 651 134 Os 3306 787 137 135 2237 556 134 Ni 1728 1358 430 338 125 128 Pd. Ag 1828 1235 377 137 Pt 144 Au 2041 566 368 669 136 139 Zn see text 693 130 137 Hg see text 234 61 Al Cd In Sn see text see text see text 594 430 505 112 243 302 152 167 158 TI Pb 144 155 933 330 143 Ga see text 303 277 153. 577 182 15 Bi t 544 195 210 171 175 182