Question

what is the center of an atom; made up of protons and
solid
nucleus
energy level
compound
which is a positively charge subatomic particle in the n
electron
neutron
element
proton
which is a neutral subatomic particle in the nucleus of a
electron
neutron
compound

Explanation:

An atom consists of a nucleus (center) containing protons (positively - charged) and neutrons (neutral), with electrons (negatively - charged) orbiting around the nucleus. A solid is a state of matter, an energy level refers to the electron's position around the nucleus, and a compound is a substance made of two or more elements. An element is a pure substance, not a subatomic particle.

Answer:

1. The center of an atom made up of protons (and neutrons) is the Nucleus.
2. A positively - charged subatomic particle in the nucleus is the Proton (the selected option "Electron" in the image is incorrect as electrons are negatively charged and orbit the nucleus).
3. A neutral subatomic particle in the nucleus is the Neutron.