Give the actual ground-state electron configuration for copper (Cu) using the complete form.
Express the electron configuration using superscripts where appropriate.
For example, the configuration for Li would be entered as 1s^22s^1.
Concepts and Reason
Electronic configuration is the electron distribution of a particular atom in its molecular orbitals. In quantum mechanics, ground state is defined as the state, which has the lowest possible energy. It is also referred to as zero-point energy. Thus, the electron arrangement of an atom in accordance with the energy level at its minimum value, represents the ground state electron configuration of an atom.
There are three basic rules for electron configuration namely, Hund’s rule, Aufbau’s principle and Pauli-exclusion principle. Hund’s rule states that an electron to double occupy a degenerate orbital, must first occupy them singly. Aufbau’s principle states that electron of an atom, always occupy the orbital in the increasing order of energy, that is, ‘s’ orbital, followed by ‘p’ orbital, followed by ‘d’ orbital, followed by ‘f’ orbital. According to Pauli-exclusion principle, any single electron can be described on the basis of four different sets of quantum number, which needs to vary in at least one. It implies that for any two different electrons, either one of the magnetic quantum number (ml), orbital angular momentum quantum number (l), spin magnetic quantum number (ms) or principal quantum number (n) needs to vary.
In order to write the electron configuration, the occupancy order of the orbitals is needed to be determined first along with their principal quantum number. The occupancy order for the orbitals has been shown as follows:
The determination of the increasing order of the orbitals occupancy would help in placing the electron of any atom in the specific orbital.
Once the increasing order of the orbital occupancy has been determined, electrons can be then placed in those orbitals. The electron configuration for copper (Cu), having atomic number 29 (which is equal to the number of electrons) has been shown below:
In the above electron configuration of the Ru, the exponential power to the orbitals represents the number of electrons present in the specific orbitals. The orbital occupancy of electrons for ‘s’ orbital is 2, for ‘p’ orbital occupancy is 6, for ‘d’ orbital occupancy is 10 and for ‘f’ orbital occupancy is 14 electrons. Furthermore, the last ‘s’ orbital of copper half filled, in order to completely fill the last ‘d’ orbital. This would result in the higher stability of the copper atom. Also, because the 3d orbital is much bigger than the 4s orbital, which pulls the one electron from the 4s orbital.