True or false: Neutrons are located in shells around the nucleus.

This is false. Neutrons are located in the nucleus which is at the center of the atom.

An atom is made up of three types of subatomic particles:

Protons are positively charged particles that are in the nucleus. The have a mass of approximately one atomic mass unit (amu).

Neutrons are electrically neutral. They also have a mass of approximately one mass unit.

The nucleus contains nearly all of the atom's mass, but makes up...

This is false. Neutrons are located in the nucleus which is at the center of the atom.

An atom is made up of three types of subatomic particles:

Protons are positively charged particles that are in the nucleus. The have a mass of approximately one atomic mass unit (amu).

Neutrons are electrically neutral. They also have a mass of approximately one mass unit.

The nucleus contains nearly all of the atom's mass, but makes up a very small part of its volume.

Electrons are located outside the nucleus, in energy levels called shells. Electrons have a very small mass that is approximately zero mass units and have a negative electrical charge. Outer electrons can be lost or gained, forming charged particles called ions.

Electron shells are mathematical functions that describe the energy of electrons. An electron shell's energy level corresponds to its distance from the nucleus. Electrons have more energy when they're at a greater distance from the nucleus.