Part AGold-191 undergoes electron capture. Express your answer as a nuclear equation. Part BGold-201 decays to a mercury isotope. Express your answer as a nuclear equation. Part CGold-198 undergoes beta emission. Express your answer as a nuclear equation. Part DGold-188 decays by positron emission. Express your answer as a nuclear equation.

A)

B)

C)

D)  

Explanation:

A) The reaction of electron capture is:

Where:

A: is the mass number = n + Z  

Z: is the number of protons

n: is the number of neutrons                  

In electron capture reaction a proton of the atom is converted into a neutron and an electron neutrino () is emitted.      

Hence, for the Gold-191 we have:

B) The nuclear reaction of the decay of Au-201 to Hg-201 is:

The above reaction is a beta decay reaction, in which a positron and electron antineutrino () are emitted from the Au-201 nucleus and a neutron is converted to a proton (n-1 and Z+1; A remains constant).        

C) The nuclear reaction of beta emission Au-198 is:

Same as above, a beta emission produces the emission of a positron and electron antineutrino () and the conversion of a neutron into a proton.    

D) Gold-188 decays by positron emission:      

In a positron emission, we have that a proton of Au-188 is converted into a neutron and a positron (e⁺) and an electron neutrino () are released.  

I hope it helps you!