A beaker of black powder can be a mixture with different substances (i.e gunpowder: a mixture of sulfur, charcoal, etc.), an element which can probably be carbon (known as black), and a compound as well which can be potassium nitrate. Hence, the answer is D.
A. an ion
The atom gains a net electrical charge if the number of protons and electrons are not equal which makes it an ion.
A covalent bond would happen
