Demonstrating that an Argument is Invalid, philosophy homework help

Capital punishment kills a human being. It is wrong to kill a human being except in self-defense. So capital punishment is wrong.Is my topic for this assignment.Put the argument into standard form,clearly identifying the premises and conclusion. Once you have done so thendemonstrate that the argument is invalid in one of two ways: Either explain ascenario in which the premises could be true and the conclusion false, or findanother argument with the same form that has true premises and a falseconclusion. Once you have done so, make sure to explain how your argumentrefutes the validity of the original argument. Mention if you think that thereis anything that could be done to make the original argument valid.