Question

What kind of decay, and why, would you expect from each of the following? Note that if you look these up on the internet, you may find that each decays by more than one mechanism. The only correct/acceptable answers will be those that could be reasonably predicted based upon nuclear makeup.

S-35

Ac-226

C-11

Ti-52

Md-257

O-15

Answer 1

a) Sulfur-35 : It is unstable nuclei and undergo electron decay

Negative Beta decay :    ₁₆S³⁵ ------------> ₁₇Cl³⁵ + _-1⁰

   Sulphur Chlorine

b) Actinium 226 : It is unstable nuclei and undergo 3 decays :

a) Negative Beta decay :    ₈₉Ac²²⁶ ------------> ₉₀Th²²⁶ + _-1⁰

Actinium Thorium

b) Electron capture decay : ₈₉Ac²²⁶ + _-1e⁰ ------> ₈₈Ra²²⁶

Radium

c) alpha decay : ₈₉Ac²²⁶ --------> ₈₇Fr²²² + ₂He⁴

Francium helium

C) Carbon -11 : It is unstable nuclei and undergo 2 decays :

a) Negative beta decay :    ₆C¹¹ ----------> ₅B¹¹ + _-1⁰

   Carbon Boron

b) Electron capture decay : ₆C¹¹ + _-1e⁰ ------> ₅B¹¹

D) Titanium-52 : It is unstable nuclei and undergo beta decay.

a) Negative beta decay : ₂₂Ti⁵² --------> ₂₁V⁵² + _-1⁰

   Vanadium

E) Mendelevium-257 : It is unstable nuclei and undergo 2 decays

a) Electron capture decay : ₁₀₁Md²⁵⁷ + _-1e⁰ ------> ₁₀₀Fm²⁵⁷

   Mendelevium Fermium

b) Alpha decay : ₁₀₁Md²⁵⁷ -------> ₉₉Es²⁵³ + ₂He⁴

   Einsteinium

F) Oxygen-15 : It is unstable nuclei and undergo positron decay.

a) Positron/positive electron decay : ₈O¹⁵ -------> ₇N¹⁵ + ₊₁⁰

   Nitrogen positron