When lead (IV) combines with nitrogen (valence = -3), the resulting product, lead (IV) nitride, is most accurately written as Pb3N4
The Correct Answer and Explanation is:
The correct formula for lead (IV) nitride is:
Pb₃N₄
Explanation
To determine the correct chemical formula for a compound formed between lead (IV) and nitrogen, we need to consider the charges (valencies) of both ions and balance them so the compound is electrically neutral.
Step 1: Determine the charges
- Lead (IV) means lead is in the +4 oxidation state. Its ion is Pb⁴⁺.
- Nitrogen typically forms a nitride ion, N³⁻, because it gains 3 electrons to complete its octet.
Step 2: Use the crisscross method
To balance the charges, we use the crisscross method, where the magnitude of each ion’s charge becomes the subscript of the other ion.
So:
- Pb⁴⁺ → subscript becomes 3
- N³⁻ → subscript becomes 4
This gives us: Pb₃N₄
This means:
- 3 lead (IV) ions each with a +4 charge contribute a total of +12
- 4 nitride ions each with a -3 charge contribute a total of -12
So, total charge: +12 + (-12) = 0
The compound is electrically neutral, which is required for all stable ionic compounds.
Naming the Compound
Since lead is a transition metal and can have multiple oxidation states, we use Roman numerals to indicate its oxidation state. In this case, lead is in the +4 state, so the correct name is:
Lead (IV) nitride
Summary
- Lead (IV) ion = Pb⁴⁺
- Nitride ion = N³⁻
- Balanced formula = Pb₃N₄
- Name = Lead (IV) nitride
This correctly reflects the chemical combination of lead in a +4 state with nitrogen in a -3 state, forming a neutral ionic compound.
