The correct name for SnO is
a. tin oxide b. tin(II) oxide c. tin(III) oxide d. tin monoxide e. tin(I) oxide
The Correct Answer and Explanation is:
The correct name for SnO is b. tin(II) oxide.
Explanation:
Tin (Sn) is a metal that can have multiple oxidation states, primarily +2 and +4. When naming compounds containing tin and oxygen, it’s important to specify the oxidation state of tin because tin forms more than one oxide.
- SnO consists of tin and oxygen in a 1:1 ratio.
- Oxygen almost always has an oxidation state of -2.
- To balance the charge in SnO, tin must have a +2 oxidation state.
Why is it tin(II) oxide and not the others?
- a. tin oxide: This name is ambiguous. It does not specify the oxidation state of tin, which is important because tin can have multiple oxidation states (II and IV are common). So, “tin oxide” could refer to either SnO or SnO₂.
- b. tin(II) oxide: This is the correct systematic name because the Roman numeral II indicates the +2 oxidation state of tin in the compound. Sn has a +2 charge, and oxygen has a -2 charge, making the compound neutral.
- c. tin(III) oxide: Tin rarely forms a +3 oxidation state oxide. There is no common or stable Sn₂O₃ compound, so this name is not used.
- d. tin monoxide: This is an older, non-systematic name. It describes the compound literally as “one oxygen” with tin but doesn’t clearly specify the oxidation state of tin. It is sometimes used but is less precise than tin(II) oxide.
- e. tin(I) oxide: Tin(I) means tin in the +1 oxidation state, which is very rare. SnO is not tin(I) oxide because the oxidation state of tin here is +2, not +1.
Additional context:
Naming ionic compounds with transition metals or metals that have multiple oxidation states requires specifying the oxidation state with Roman numerals in parentheses (Stock system). Tin(II) oxide follows this system, ensuring clarity in chemical communication.
Thus, SnO is correctly named tin(II) oxide because tin exhibits a +2 charge, oxygen is -2, and this naming avoids ambiguity. This precision is crucial in chemistry, especially when different oxides of the same metal have vastly different properties and uses.