Copper has a moderately low ionization energy, meaning that it takes a small amount of energy to remove its valence electron. Therefore, copper is more likely to form a cation than an anion. Though the 3d subshell posses more energy than the 4s, when ionized the 4s electron is removed first to form a cation. This is due to screening from the 3d electrons. All ten electrons, shield the singular 4s electron from the effective nuclear charge of the atom, thus causing the lower energy 4s electron to act as the atom’s valence electron. This behavior is characteristic of most transition metals. The first ionization energy does not vary much across the transition metal; as a result, most transition metals have more than one oxidation energy. Copper has two. It may lose one electron from its 4s subshell to become a Cu+ ion; but it may also lose two electrons, the 4s and one from the 3d orbitals to become Cu2+
Copper has a moderately low ionization energy, meaning that it takes a small amount of energy to remove its valence electron. Therefore, copper is more likely to form a cation than an anion. Though the 3d subshell posses more energy than the 4s, when ionized the 4s electron is removed first to form a cation. This is due to screening from the 3d electrons. All ten electrons, shield the singular 4s electron from the effective nuclear charge of the atom, thus causing the lower energy 4s electron to act as the atom’s valence electron. This behavior is characteristic of most transition metals. The first ionization energy does not vary much across the transition metal; as a result, most transition metals have more than one oxidation energy. Copper has two. It may lose one electron from its 4s subshell to become a Cu+ ion; but it may also lose two electrons, the 4s and one from the 3d orbitals to become Cu2+