Question

which is a characteristic of the part of the atom marked \a\? it contains most of the mass. it is negatively charged. it is mostly empty space. it is composed of electrons.

Explanation:

The part marked "A" in the atom diagram is the electron - shell region. Electrons are negatively charged and are located in these regions around the nucleus. The nucleus contains most of the mass. The nucleus is composed of protons and neutrons, not electrons. The electron - shell region is not mostly empty space in the sense that it contains electrons. Since electrons are negatively charged, the part marked "A" is negatively charged.

Answer:

It is negatively charged.