Final answer:
Lithium is the highly reactive metal used in manufacturing synthetic rubber and drugs. One of its compounds is used to treat mental illnesses successfully.
Step-by-step explanation:
The highly reactive metal used in the manufacture of synthetic rubber and drugs, and one of its compounds used to successfully treat a certain type of mental illness is Lithium.
Lithium compounds are commonly used in greases, batteries, and as drugs for treating manic-depressive or bipolar behavior.
Its compounds are also used in drugs to treat mental illnesses such as bipolar disorder.