Question

what charge does al typically have in ionic compounds, and why?
a +1, because in the ground state it has one unpaired electron.
b +2, because it has two electrons in the 2s subshell.
c +3, because it has three valence electrons.
d +4, because it is in the fourth row of the periodic table.

Explanation:

Step1: Analyze the valence electrons of Al

Aluminum (Al) has an atomic number of 13. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}\). The valence electrons are in the \(3s\) and \(3p\) sub - shells. The number of valence electrons is \(3\) ( \(2\) in \(3s\) and \(1\) in \(3p\)).

Step2: Determine the ionic charge

In ionic compounds, metals tend to lose their valence electrons to achieve a stable electron configuration. Al loses its \(3\) valence electrons. When it loses \(3\) electrons, it forms \(Al^{3 +}\) ion.

Answer:

C. +3, because it has three valence electrons.