give the ground-state electron configuration for copper (cu) using noble-gas shorthand
The Correct Answer and Explanation is:
The ground-state electron configuration for copper (Cu) using noble-gas shorthand is:
[Ar]3d104s1\text{[Ar]} 3d^{10} 4s^1[Ar]3d104s1
Explanation:
Copper (Cu) has an atomic number of 29, meaning it has 29 electrons. To determine its electron configuration, we first use the nearest noble gas, argon (Ar), which has an atomic number of 18 and provides the core electron configuration.
- Argon Configuration:
The noble gas argon has the configuration [Ar]=1s22s22p63s23p6\text{[Ar]} = 1s^2 2s^2 2p^6 3s^2 3p^6[Ar]=1s22s22p63s23p6. This accounts for the first 18 electrons. - Remaining Electrons:
After argon, we have 29 – 18 = 11 electrons left to place in the orbitals of the next energy levels, primarily 3d and 4s orbitals. - 4s and 3d Orbitals:
- The next available orbitals after argon are the 4s and 3d orbitals. The 4s orbital fills first, as it is at a lower energy level than 3d.
- Typically, the 4s orbital would receive two electrons, but copper has an anomalous electron configuration due to a slight difference in energy between the 4s and 3d orbitals.
- Electron Configuration Anomaly:
Copper’s electron configuration is an exception because filling the 3d orbital first results in a more stable arrangement. Thus, copper’s electron configuration is: [Ar]3d104s1\text{[Ar]} 3d^{10} 4s^1[Ar]3d104s1 This configuration minimizes the energy of the atom, as a completely filled 3d subshell (3d103d^{10}3d10) provides added stability, making the 4s orbital half-filled instead of fully occupied.
Key Points:
- Noble-Gas Shorthand: Uses the nearest noble gas (argon in this case) to simplify the electron configuration.
- Anomalous Filling: Copper deviates from the expected configuration to achieve greater stability by having a filled 3d orbital and a single electron in the 4s orbital.
