A less common type of radioactive particle emitted is the positron. If potassium-38 forms argon-38 by positron emission, the number of a positron is and the charge is

Potassium goes to argon so that a proton in the K nucleus "vanishes" into a positron (positive electron?) but keeps the same atomic mass at 38.? I'd say that the number of the positron was 0, and the charge was + 1 electronic charge.