Question

Determine the formal charge of each element in the following:

a) H₂O
b) NH₄⁺
c) CO₃²⁻
d) SO₄²⁻

Answer 1

To determine the formal charge of each element in a molecule, count the number of valence electrons, assign bonding electron pairs, and calculate the formal charge by subtracting lone electrons from assigned electrons. The correct option is d.

Step-by-step explanation:

In order to determine the formal charge of each element in a molecule, you need to follow these steps:

1. Count the number of valence electrons for each atom. This can be done by referring to the periodic table and considering the element's group number.
2. Assign each bonding electron pair to the more electronegative atom. Electronegativity is a measure of an element's ability to attract electrons.
3. Calculate the formal charge by subtracting the number of lone electrons from the number of assigned electrons for each atom.

For example, in H2O, each hydrogen atom has a formal charge of +1 and the oxygen atom has a formal charge of -2. In NH4+, each hydrogen atom has a formal charge of +1 and the nitrogen atom has a formal charge of -3.

In CO32-, each oxygen atom has a formal charge of -1 and the carbon atom has a formal charge of +2. Finally, in SO42-, each oxygen atom has a formal charge of -1 and the sulfur atom has a formal charge of +2. The correct option is d.