Bromine, atomic weight physical properties

Prepare a table showing the relation between chlorine, bromine, and iodine. The table should include the atomic weight, physical state, color, typical method of preparation, properties, and analogous compounds. 

The assumption that PBBs and PBDEs share many toxicological characteristics with PCBs also does not consider geometrical differences due to the higher atomic weight and considerably larger molecular volume of bromine compare to chlorine (Hardy 2000, 2002). These differences contribute to dissimilar physical/chemical properties that can influence the relative toxicokinetics and toxicities of the chemicals. 

Some of the physical characteristics of the synthesized PPOBr are shown in Table 1. The data in Table 1 indicate that there exists a direct correlation between the degree of bromination of PPO and their physical properties. The densities of PPO increase with an increase in the degree of bromination. The high density of the brominated PPO is attributed to the heavy bromine substituents. The Tg of the brominated PPO was higher than that of unmodified PPO and increase with an increase in the degree of bromination. This is probably due to the reduced torsional motion of the repeat unit caused by the bulky bromine atom. Similar trends have been reported for brominated low molecular weight (0.49 dL/g) PPO [6, 16]. Since polymer with stiff backbones often demonstrate high Tg, one may conclude that bromination of PPO increases polymer chain stiffness. 

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