We’re being asked to determine the **formal charge of ALL ELEMENTS **in **H _{3}O^{+}, SO_{4}^{2-} and NH_{3}.**

**To do so, we need to do the following steps:**

*Step 1:* Determine the central atom in the molecule.

*Step 2:* Calculate the total number of valence electrons present.

*Step 3:* Draw the Lewis structure for the molecule.

*Step 4:* Calculate the formal charge for the indicated atom.

Recall that the formula for the ** formal charge** is:

$\overline{){\mathbf{F}}{\mathbf{.}}{\mathbf{C}}{\mathbf{.}}{\mathbf{=}}{\mathbf{Group}}{\mathbf{}}{\mathbf{No}}{\mathbf{.}}{\mathbf{}}{\mathbf{-}}\left(\mathbf{Bonds}\mathbf{+}\mathbf{Nonbonding}\mathbf{}\mathbf{electrons}\right)}$

Determine the formal charge of each element in the following:

(a) H_{3}O^{+}

(b) SO_{4}^{2−}

(c) NH_{3}

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Formal Charge concept. You can view video lessons to learn Formal Charge. Or if you need more Formal Charge practice, you can also practice Formal Charge practice problems.