Question

Think of forming an ionic compound as three steps (this is a simplification, as with all models): (1) removing an electron from the metal; (2) adding an electron to the nonmetal; and (3) allowing the metal cation and nonmetal anion to come together. e. Given your above explanations, why is NaCl stable but not Na₂Cl? NaCl₂? What about MgO compared to MgO₂? Mg₂O?

Answer 1

NaCl is stable because sodium loses one electron to form the
`Na^(+)` cation, while chlorine gains one electron to form the
`Cl^(-)` anion. On the other hand,
`Na_(2) Cl` and
`NaCl_(2)` are not stable because the ratios of cations to anions are incorrect. In the case of MgO, magnesium (Mg) loses two electrons to form the
`Mg^(2+)` cation, while oxygen (O) gains two electrons to form the
`O^(2-)` anion.

An ionic compound is formed in three steps: removing an electron from the metal, adding an electron to the nonmetal, and allowing the metal cation and nonmetal anion to come together. NaCl is stable because sodium (Na) loses one electron to form the cation,
`Na^(+)`, while chlorine (Cl) gains one electron to form the
`Cl^(-)` anion. The electrostatic attraction between the
`Na^(+)` and
`Cl^(-)` ions makes NaCl stable.

In
`Na_(2) Cl`, there are two sodium ions (
`Na^(+)`) for every one chloride ion (
`Cl^(-)` ), which results in an unstable ratio. Similarly,
`NaCl_(2)` has one sodium ion (
`Na^(+)`) for every two chloride ions (
`Cl^(-)` ), which also creates an unstable ratio.

In the case of MgO, magnesium (Mg) loses two electrons to form the
`Mg^(2+)` cation, while oxygen (O) gains two electrons to form the
`O^(2-)` anion. The resulting compound, MgO, is stable because of the electrostatic attraction between the
`Mg^(2+)` and
`O^(2-)` ions.

However,
`MgO_(2)` and
`Mg_(2) O` are not stable due to incorrect cation to anion ratios.
`MgO_(2)` has one magnesium ion (
`Mg^(2+)`) for every two oxygen ions (
`O^(2-)`), creating an unstable ratio.
`Mg_(2) O` has two magnesium ions (
`Mg^(2+)`) for every one oxygen ion (
`O^(2-)`), also resulting in an unstable ratio.