Explain, using the electron configuration of Al, why aluminum has a +3 charge.
The correct answer and explanation is:
The electron configuration of aluminum (Al) is:
1s22s22p63s23p11s^2 2s^2 2p^6 3s^2 3p^1
Aluminum has an atomic number of 13, meaning it has 13 electrons in its neutral state. The configuration shows that the first energy level (1s) holds 2 electrons, the second level (2s and 2p) holds 8 electrons, and the third level (3s and 3p) holds 3 electrons, with one electron in the 3p orbital.
The tendency of atoms is to achieve a stable electron configuration similar to that of the nearest noble gas, which in this case is neon (Ne), with the configuration 1s22s22p61s^2 2s^2 2p^6. For aluminum to reach this stable configuration, it needs to lose three electrons from its outermost shell (the 3s and 3p orbitals), leaving it with a configuration of 1s22s22p61s^2 2s^2 2p^6, which mirrors neon’s electron structure.
When aluminum loses three electrons, it forms a positive ion with a charge of +3, since the loss of negatively charged electrons results in a net positive charge. The process of ionization for aluminum can be summarized as:
Al→Al3++3e−Al \rightarrow Al^{3+} + 3e^-
Thus, aluminum achieves the stable electron configuration of neon, and its resulting ion has a charge of +3. This is why aluminum commonly forms a +3 ion, which is highly stable. The +3 charge is characteristic of metals in Group 13 of the periodic table, as they tend to lose three electrons to reach a noble gas-like configuration.