What are the parts of the atom & which one is gained or lost in order for an object to obtain a charge?

The parts of an atom are electrons, usually found in an electron shell around the nucleus of the atom, and protons and neutrons, found in the nucleus of the atom. Typically, electrons are gained or lost in order to obtain charge.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).