The two elements that produce background radiation on earth are Radon and Uranium. Airborne radon can decay on its own. Radon undergoes alpha decay to produce Polonium. Uranium naturally undergoes alpha decay to produce Thorium.
Answer:
7 is the mass number of li and 3 is the atomic number
a 3
b 7
c 3
d 4
invisable
you probably dont want to put that...
