Apositively charged substance is brought near the ion. what will most likely happen and why

It repels positive ion and attracts negative ion.

Explanation:

There are 2 types of ions:

1. Cations: These ions are positively charged ions which are formed when a substance looses electrons.

2. Anions: These ions are negatively charged ions which are formed when a substance gains electrons.

It is known that, like charges repel each other and unlike charges attract each other.

As, it is given that the substance is positively charged, so it will attract anion and repel cation.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.