Many radioactive atoms that have large masses undergo radioactive decay by releasing a particle that is identical to a helium-4 nucleus.

what changes in the original atom are expected as a result of this natural phenomenon?

a. the atomic number and the mass number will decrease.

b. the atomic number and the mass number will increase.

c. the atomic number will increase, and the mass number will decrease.

d. the atomic number will decrease, and the mass number will increase.

A. The atomic number and the mass number will decrease.

Explanation:

Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the atomic number and mass number is decreased by 2 and 4 units respectively.

General representation of an element is given as:  

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

General representation of alpha decay :

c. 4.54 x 10–12 j happens to be correct