Rare earth elements are essential materials for the manufacture of electronic devices.

An isotope refers to elements with the same atomic number but different numbers of neutrons.

His body showed a rejection reaction to the transplanted organ.

She overreacted to his words.

Nuclear reactions are used for mass production of energy.

His single word triggered a chain reaction, and everything changed.

I was surprised by his overreaction.

This reaction occurs through a chemical process.

He is an excellent chemist who made many discoveries.

He is an expert in petrochemistry.