the thallium nucleus is radioactive, with a half-life of approximately 3.0 min. at a given instant, the activity of a certain sample of thallium is 2400 bq. using the concept of half-life, what is the approximate activity of the sample 9 minutes later?

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.