Question

Lanthanum-140 is a radioactive isotope. A nucleus of lanthanum-140 emits gamma radiation. What happens to the mass number and the charge of the nucleus when gamma radiation is emitted?

a. mass number stays the same, charge stays the same
b. mass number increases, charge stays the same
c. mass number stays the same, charge decreases
d. mass number decreases, charge increases

Answer 1

When lanthanum-140 emits gamma radiation, both the mass number and the charge of the nucleus stay the same because gamma radiation consists of high-energy photons that do not affect the nucleus's mass or charge.

Step-by-step explanation:

When a nucleus of lanthanum-140 emits gamma radiation, it is releasing energy in the form of photons. The emission of gamma radiation does not involve a change in the number of protons or neutrons in the nucleus. Therefore, both the mass number and the charge of the nucleus remain unchanged.

Thus, the correct answer to what happens to the mass number and the charge of the nucleus when gamma radiation is emitted is: a. mass number stays the same, charge stays the same. This is because gamma radiation consists of high-energy photons that do not carry mass or charge, merely decreasing the energy of the emitting nucleus without altering its composition.