Resonance

[Jarrett Peyrefitte 2K]

Can someone explain what resonance is and what the importance of it is?

[JohnWalkiewicz2J]

Resonance occurs when some lewis structures have multiple bonds in different equivalent locations. For instance, for the lewis structure for a Nitrate ion (NO3)- , the double bond can alternate between the nitrogen and the three oxygen atoms. Typically when you draw resonate structures, that compound is going to be more stable.

[005384106]

I didn’t understand why oxygen received a negative charge instead of silver. Can someone please explain this to me?

[005384106]

Why does sulfur have a double bond in the Lewis structure instead of leaving the electrons as valence electrons?

[005384106]

Why does sulfur have a double bond in the Lewis structure instead of leaving the electrons as valence electrons?

I am referring to this problem that we did during lecture.

[Zaynab Hashm 2I]

Can someone explain what resonance is and what the importance of it is?

Resonance is a way of describing bonding that might form different structures of a certain molecule or ion where the chemical connectivity is the same but the electrons are distributed differently around the structure. It basically describes the delocalization of electrons within molecules or ions, which happens because electrons can flow through the system.

It's important because it visually demonstrates the different structures and the type of bonds between the atoms (single or double or triple). It also shows then by calculating the formal charge (FC) which structure is the most stable.

[lilymayek_1E]

I didn’t understand why oxygen received a negative charge instead of silver. Can someone please explain this to me?

This has to do with the formal charge, or gaining/losing electrons when forming bonds. this is found with the equation FC = V - (L+(S/2)). To find the formal charge of oxygen in this particular compound, you take the number of valence electrons (in this case, 6), subtracted by lone pair electrons plus shared electrons (6+(2/2). For an oxygen atom, you get a formal charge of -1. That's why oxygen receives a negative charge.
Conceptually, oxygen is a more electronegative atom-where it'll pull electrons more toward itself, offset by sulfur (instead of silver?at least that was the example lavelle gave.), which thus has a more positive charge. That positive charge can be found by the FC equation as well.

[Madeline Phan 1E]

I didn’t understand why oxygen received a negative charge instead of silver. Can someone please explain this to me?

Oxygen gets the negative charge because it has a higher electronegativity than sulfur. If you look at the periodic table, oxygen and sulfur are in the same group but oxygen is above sulfur. Electronegativity decreases as you go down the periodic table, so oxygen has a higher electronegativity, meaning it has a higher affinity to gain electrons. This is why it should receive the negative charge as it is more prone to receiving electrons than sulfur is.