In a pure element, what is the oxidation state?

In a pure element, what is the oxidation state?

• A. +1
• B. zero
• C. -1
• D. varies

Answer: (B)

The oxidation state is a bookkeeping number that represents the hypothetical charge on an atom if electrons were assigned to the more electronegative partner in a compound. In a pure element there are no bonds to other elements, so there is no transfer of electrons. Each atom is in its elemental form with its normal electrons, giving it an oxidation state of zero. This applies to diatomic molecules like O2, N2, H2, and to metals in their solid elemental form. Only when the element forms compounds or ions does the oxidation state become positive or negative depending on electron transfer. So zero is the correct oxidation state for a pure element.

The oxidation state is a bookkeeping number that represents the hypothetical charge on an atom if electrons were assigned to the more electronegative partner in a compound. In a pure element there are no bonds to other elements, so there is no transfer of electrons. Each atom is in its elemental form with its normal electrons, giving it an oxidation state of zero. This applies to diatomic molecules like O2, N2, H2, and to metals in their solid elemental form. Only when the element forms compounds or ions does the oxidation state become positive or negative depending on electron transfer. So zero is the correct oxidation state for a pure element.