Modern periodic table is based upon atomic number. Explain what does the modern periodic table states about the atomic numbers ?

Explanation:Elements of the periodic table are arranged in order of increasing atomic number. The periodic law states “When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties.”

b is the correct

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.