If I am reading this correctly, then mercury-198 will receive a neutron, decay to mercury-197, then emit an electron to become gold-197.

Mercury has seven stable isotopes ranging from 195 to 204, so purifying to 198 is challenging (this isotope is 10% of the metal's occurrence). Would this require centrifuges as uranium does?

The decay chains of the other isotopes would be different.

https://en.wikipedia.org/wiki/Synthesis_of_precious_metals#G...

"...the production cost is estimated to be a trillion times the market price of gold."

The above reaction is at the end of the section.

No it really isn't. People have transmuted a few hundred milligrams of mercury into gold in the lab with multi-million dollar machines, but that doesn't make it economically viable in the slightest.