Question

given the following mystery ions, \\(x^{3+}\\) \\(m^{2-}\\) \\(q^{2+}\\) \\(j^-\\) which formula would not be correct for an ionic compound? a \\(q_2m_2\\) b \\(qj_2\\) c \\(x_2m_3\\) d \\(xj_3\\)

Explanation:

To determine the correct ionic compound formula, we use the criss - cross method, where the charge of one ion becomes the subscript of the other.

Step 1: Analyze Option A ($Q_2M_2$)

• The ion $Q$ has a charge of $2 +$ ($Q^{2+}$) and the ion $M$ has a charge of $2 -$ ($M^{2 -}$).
• Using the criss - cross method, the formula should be $Q_2M_2$? Wait, no. Let's do it properly. The ratio of $Q^{2+}$ to $M^{2 -}$: the magnitude of the charges are equal (2 and 2). So the formula should be $QM$ (since the subscripts of 2 can be simplified by dividing by 2). So $Q_2M_2$ is not the simplest form and is incorrect. But let's check other options to be sure.

Step 2: Analyze Option B ($QJ_2$)

• $Q$ is $Q^{2+}$ and $J$ is $J^-$.
• Using criss - cross: the charge of $Q$ (2) becomes the subscript of $J$, and the charge of $J$ (1) becomes the subscript of $Q$. So the formula is $Q_1J_2$ or $QJ_2$. This is correct.

Step 3: Analyze Option C ($X_2M_3$)

• $X$ is $X^{3+}$ and $M$ is $M^{2 -}$.
• Criss - cross: charge of $X$ (3) becomes subscript of $M$, charge of $M$ (2) becomes subscript of $X$. So the formula is $X_2M_3$. This is correct.

Step 4: Analyze Option D ($XJ_3$)

• $X$ is $X^{3+}$ and $J$ is $J^-$.
• Criss - cross: charge of $X$ (3) becomes subscript of $J$, charge of $J$ (1) becomes subscript of $X$. So the formula is $X_1J_3$ or $XJ_3$. This is correct.

Answer:

A. $Q_2M_2$