Final answer:
In beta minus decay, the Z number of an element increases by 1 while the mass number stays the same. This is because a neutron is converted into a proton, and an electron is emitted, changing the element into the next higher element on the periodic table.
Step-by-step explanation:
In beta minus decay, the atomic number, often represented as the Z number, increases by 1. This type of decay involves a neutron in the nucleus being converted into a proton, which results in the emission of an electron (also known as a beta particle) and a neutrino. The mass number, or A number, remains the same because the proton that is formed has the same mass as the neutron that was converted. The newly formed proton increases the Z number of the element, thereby transforming the element into a new element with a higher atomic number in the periodic table. For instance, carbon-14 (14C) decays into nitrogen-14 (14N), with the Z number increasing from 6 to 7.
Example of Beta Minus Decay
Following the beta decay process:
14C → 14N + e⁻ + ν
The carbon-14 nucleus undergoes beta decay to become a nitrogen-14 nucleus. The atomic number (Z number) of the resulting nucleus (nitrogen) is 7, which is one more than that of the original carbon nucleus, illustrating the increase in atomic number.