Which sample is a pure substance?
a test tube of zinc oxide
a container of zinc and oxygen
a flask of pond water
a jar of soil

a test tube of zinc and oxygen

Explanation:

i just did on edgen

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a

answer:

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