Skip to main content
Ch.10 - Chemical Bonding I: The Lewis Model
Chapter 10, Problem 68

Write a Lewis structure that obeys the octet rule for each ion. Include resonance structures if necessary and assign formal charges to each atom. a. ClO3- b. ClO4- c. NO3- d. NH4+

Verified step by step guidance
1
Identify the total number of valence electrons for each ion. For example, for ClO3-, count the valence electrons from Cl and O atoms, and add one extra electron for the negative charge.
Draw a skeletal structure for each ion, connecting the central atom to surrounding atoms with single bonds. Typically, the least electronegative atom is the central atom.
Distribute the remaining valence electrons as lone pairs to complete the octet for the surrounding atoms first, then place any remaining electrons on the central atom.
If the central atom does not have a complete octet, consider forming double or triple bonds by converting lone pairs from surrounding atoms into bonding pairs.
Check for resonance structures by moving electrons around to see if different valid structures can be formed. Assign formal charges to each atom using the formula: Formal Charge = (Valence electrons) - (Non-bonding electrons) - 0.5*(Bonding electrons).

Verified Solution

Video duration:
1m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Lewis Structures

Lewis structures are diagrams that represent the bonding between atoms in a molecule and the lone pairs of electrons that may exist. They are essential for visualizing the arrangement of electrons and understanding molecular geometry. In these structures, dots represent valence electrons, and lines represent covalent bonds. Drawing Lewis structures helps predict the stability and reactivity of molecules.
Recommended video:
Guided course
04:28
Lewis Dot Structures: Ions

Octet Rule

The octet rule is a chemical guideline stating that atoms tend to bond in such a way that they each have eight electrons in their valence shell, achieving a stable electron configuration similar to that of noble gases. This rule is particularly applicable to main group elements and helps in predicting the formation of ions and molecules. However, there are exceptions, especially for elements in the third period and beyond, which can accommodate more than eight electrons.
Recommended video:

Formal Charge

Formal charge is a concept used to determine the charge distribution within a molecule or ion, calculated by comparing the number of valence electrons in the free atom to the number of electrons assigned to it in the Lewis structure. It helps assess the stability of a structure; ideally, the formal charges should be minimized, and the most stable structures have formal charges close to zero. Assigning formal charges is crucial when evaluating resonance structures and determining the most favorable Lewis structure.
Recommended video:
Guided course
01:53
Formal Charge