Alpha decay of an element.

a. maintains the atomic mass
b. lowers the atomic number
c. raises the atomic number
d. maintains the atomic number

Alpha decay lowers the atomic number of an element. The correct option is B. Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle, which is an helium particle. During this process, the atomic number of the nucleus is reduced by two and the mass number is reduced by 4.