if 8.0 mg of a radioactive substance naturally decays to 0.50 mg over 184 days, what is the half-life of the radioisotope?

Copper, silver, aluminum, cobalt, chromium, mercury 

If you open the bottle of perfume then nothing but the smell will come out of it and yes it is a type of gas smell because it’s say it in english so i can understand better and you

Iam not going to tell you

Answerbonded to an amino group(nh2);