What makes elements and compounds different from mixtures? Elements and compounds–
have a constant composition.
are made of gases.
will not change when heated.
conduct electric current.

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.

explanation:

0.07 g/cm³

1.37 g/cm³