Answer:
stable nuclei are silicon-28, zinc-64
, potassium-40
while unstable one are arsenic-82
, radium-228
Explanation:
There is rule to predict stability of a nuclei that is
Z <= 20 N/Z = 1 most stable
Z = 20-40 N/Z = 1.25 stable
Z = 40-80 N/Z = 1.80 less stable
Z >= 83, nucleus becomes unstable or radioactive
Here, N/Z = no. of neutrons/ No. of protons
1. silicon-28 , N/Z =14/14 = 1 stable
2. arsenic-82, N/Z = 49/33 = 1.48 (unstable)
3. Potassium-40 , N/Z = 21/19 = 1.10(stable)
4. zinc-64, N/Z =34/30 = 1.13 (stable)
5. radium-228 (unstable, radioactive)
Therefore, stable nuclei are silicon-28, zinc-64
, potassium-40
while unstable one are arsenic-82
, radium-228
