What is the best way to insulate a recording studio from outside sound

This question is about electrolysis. metal spoons can be coated with silver. this is called electroplating. suggest one reason why spoons are electroplated?

Avariable that is not being directly tested during an experiment should be

Which of the following nuclei would be the least stable a 2 protons, 2 neutrons b 1 proton 1 neutron c 1 proton 3 neutrons d 1 proton 2 neutrons