Question

difference between radiosctivity substance and radiation

Answer 1

Radioactivity and radiation are often used interchangeably, but they describe different (yet related) processes. But before going into this difference, it's useful to understand what atoms are and a few concepts about how they behave. An atom is the smallest particle that can be described as a chemical.

Answer 2

redioactivity is the phenomenon that exists with an radioactive element either by fusion or  fission reaction it liberates energy !!!!!!
while
Radiation energy travelling in the form of particles or waves in bundles of energy called photons. Some everyday examples are microwaves used to cook food, radio waves for radio and television, light, and x-rays used in medicine.