Explain the difference between Carbon-9 and Carbon-14. Which version Carbon do you believe is the most stable? Why? What information could help you confirm your prediction?

correct form of question is

Explain the difference between Carbon-12 and Carbon-14. Which version Carbon do you believe is the most stable? Why? What information could help you confirm your prediction?

Carbon has three isotopes those are carbon- 12 , carbon - 13 , carbon-14 among these only C-12 and C-13 are stable while C-14 is radioactive.

C-12 has 6 protons and 6 neutrons , C-14 has 6 protons and 8 neutrons. Atoms with equal number of protons and electrons are generally stable however C-12 and C-14 have 6 electrons but due to excess neutrons present in C-14 makes it undergo radioactivity therefore it is unstable.