#2.5
know the colours, physical states (at room temperature) and trends in physical properties of these elements
#2.6
use knowledge of trends in Group 7 to predict the properties of other halogens
#2.7
understand how displacement reactions involving halogens and halides provide evidence for the trend in reactivity in Group 7
#2.8C
explain the trend in reactivity in Group 7 in terms of electronic configurations