Question

question 9 (1 point)
when a neutron is emitted from an unstable nucleus, the atomic mass number of the
nucleus
increases by 1.
decreases by 1.
does not change.
none of the given answers

Explanation:

The atomic mass number is the sum of protons and neutrons in a nucleus. A neutron has a mass number of 1. When a neutron is emitted, the number of neutrons decreases by 1, so the total mass number (protons + neutrons) also decreases by 1.

Answer:

B. decreases by 1.