What kind of electrons participate in electrical conductivity?

The correct answer is valence electrons because they are the electrons that are located in the outermost shell of an atom and are primarily responsible for forming bonds and conducting electricity. In metals, valence electrons are often loosely bound and can move freely between atoms, which allows for the flow of electrical current. This mobility is what makes metals generally good conductors of electricity.

Core electrons, on the other hand, are found in the inner shells of atoms and do not participate in bonding or conduction because they are more tightly bound to the nucleus. Shielding electrons are similar in that they also refer to those electrons that protect the nucleus from the attractions of outer electrons. Unpaired electrons can contribute to magnetic properties but do not directly correlate with general electrical conductivity in the way that valence electrons do.

Thus, it is the valence electrons that play a crucial role in electrical conductivity, making this answer the most accurate in relation to the question.