What is an example of a radioactive rate earth metal in the periodic table ?

All isotopes of promethium are radioactive, and it does not occur naturally in the earth's crust; however, a trace amount is generated by decay of uranium 238. They are often found in minerals with thorium, and less commonly uranium

Explanation:

Explanation:  All isotopes of promethium are radioactive, and it does not occur naturally in the earth's crust; however, a trace amount is generated by decay of uranium 238. They are often found in minerals with thorium, and less commonly uranium.

smooth muscle is composed of involuntary muscles found within the walls of organs and structures such as the esophagus, stomach, intestines, and blood vessels. those muscles push materials like food or blood through organs. unlike skeletal muscle, smooth muscle can never be under your control.

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.