During nuclear decay, if the atomic number decreases by one but the mass number is unchanged, the radiation emitted is

a positron
an alpha particle
a beta particle
none of these choices are correct

A beta particle

Explanation:

The radioactive particle must undergo a beta decay to have the mass number unchanged but the atomic number to have decreased by one.

This type of beta decay results in the emission of a positron which is a type of beta particle. It resembles an electron but it has a positive charge of 1.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.