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: Determine the electron configuration of Al

Aluminum (Al) has an atomic number of 13. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}\). In the ground state, it has three valence electrons (\(3s^{2}3p^{1}\)).

Step2: Analyze the formation of ionic compounds

When forming ionic compounds, metals tend to lose electrons to achieve a noble - gas configuration. Al loses three electrons (\(3s^{2}3p^{1}\) electrons) to form \(Al^{3 +}\) with the electron configuration \(1s^{2}2s^{2}2p^{6}\) (similar to neon).

Answer:

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