Formal Charge Made Simple: A Guide to Molecular Stability

The video tutorial explains the concept of formal charge in Lewis structures, detailing how atoms lose or gain electrons. It defines formal charge as the difference between valence electrons in an isolated atom and those assigned in a molecule. The tutorial covers rules for calculating formal charge, emphasizing that the sum of formal charges is zero for neutral species, negative for anions, and positive for cations. Examples include phosphine, ozone, ammonium ion, and nitrate ion. The video also discusses how molecular structure affects formal charge and stability, using nitrous oxide as an example.

What is the formal charge of an atom in a polyatomic molecule based on?

• The number of neutrons in the atom

• The atomic mass of the atom

• The difference between valence electrons and assigned electrons

• The total number of protons in the atom

In a neutral molecule, what should the sum of the formal charges be?

• Equal to the number of bonds

• Zero

• Equal to the number of atoms

• Equal to the number of valence electrons

How is the formal charge of phosphorus in phosphine calculated?

• 6 valence electrons, 5 non-bonding electrons, 2 bonding electrons

• 5 valence electrons, 2 non-bonding electrons, 6 bonding electrons

• 6 valence electrons, 2 non-bonding electrons, 5 bonding electrons

• 5 valence electrons, 6 non-bonding electrons, 2 bonding electrons

Which atom in the ozone molecule has a formal charge of zero?

• All oxygen atoms

• Right oxygen

• Central oxygen

• Left oxygen

Why is the nitrous oxide structure with a negative charge on oxygen more stable?

• The structure has more bonds

• The structure has fewer atoms

• Nitrogen is more electronegative than oxygen

• Oxygen is more electronegative than nitrogen