The milligram (symbol "mg") is a unit of mass, equal to 1/000 of a gram, and 1/10000000 of a kilogram ( also written "1E-6 kg). Grams : The gram (SI unit symbol: g) is a metric system unit of mass. It is equal to one one-thousandth of the SI base unit, the kilogram, or 1E3 kg
We don't have enough information to say anything about its heat energy, its chemical energy, or the energy due to any electrical charge it may be carrying or any magnetic field it may have.
