Group 1 and 7 Periodicity

In the chapter Periodicity, under Group Trends, we observe that there are trends in the reactions of some elements. As such, these elements are in Groups.

For Group 1 Alkali Metals, we see that reactivity increases down the group. The reactions of these elements with water become increasingly vigorous. 

For Group 7 Halogens, a more reactive halogen will displace a less reactive halogen from its halide salt. The colour change may be observed below.

Take a look at the above videos!