Final answer:
In binary ionic compounds, the charge on monatomic ions can be predicted based on the positions of the atoms in the periodic table. Metals tend to lose electrons and form positive ions, while nonmetals tend to gain electrons and form negative ions.
Step-by-step explanation:
Predicting the charge on the monatomic ions formed from atoms in binary ionic compounds requires understanding the concept of valence electrons. Valence electrons are the outermost electrons of an atom that participate in chemical reactions.
a) Mg: Magnesium is a metal in Group 2 of the periodic table. Metals tend to lose electrons and form positive ions called cations. Since magnesium is in Group 2, it loses 2 valence electrons to attain a stable electron configuration. Therefore, the charge on a magnesium ion is 2+, written as Mg2+.
b) O: Oxygen is a nonmetal in Group 16 of the periodic table. Nonmetals tend to gain electrons and form negative ions called anions. Since oxygen is in Group 16, it gains 2 valence electrons to attain a stable electron configuration. Therefore, the charge on an oxygen ion is 2-, written as O2-.
c) N: Nitrogen is a nonmetal in Group 15 of the periodic table. Nonmetals tend to gain electrons and form negative ions called anions. Since nitrogen is in Group 15, it gains 3 valence electrons to attain a stable electron configuration. Therefore, the charge on a nitrogen ion is 3-, written as N3-.
d) Al: Aluminum is a metal in Group 13 of the periodic table. Metals tend to lose electrons and form positive ions called cations. Since aluminum is in Group 13, it loses 3 valence electrons to attain a stable electron configuration. Therefore, the charge on an aluminum ion is 3+, written as Al3+.