The delocalized π system in benzene is formed by a cyclic overlap of 6 orbitals.

unhybridized pi oribtals

Explanation:

The pi bond is always formed by the sideways overlap of unhybridized p-orbitals that include Py and Pz orbitals.

The 2Py and 2Pz orbiatls in each carbon atom forming the benzene ring, are unhybridized that are responsible for pi bond formation between the carbon atoms that form a benzene ring.

c is the answer because when something is left after something evaporates that shows the chemical change.

answer:

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