Transmutation
a. nuclear change.
b. chemical change.
c. both a nuclear change and a chemical change.
d. neither a nuclear nor chemical change.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.

a corroding iron, if that's one of your choices

the answer is symmetrical : )