He likes to save money.

The Jin dynasty played an important role in Chinese history.

Transition metals play an important role in chemical reactions.

When he opened the door, a metallic sound echoed.

Alkali metals are very reactive chemically.

The atomic number of helium is 2.

I learned about valence in chemistry class.

We must not forget the horror of the atomic bomb.

He measures time accurately using an atomic clock.

The safety of nuclear reactors is very important.