Final answer:
In the reaction between magnesium and oxygen, magnesium (Mg) is the element that is oxidized as it loses electrons. The correct answer is B) Mg(s).
Step-by-step explanation:
When considering the chemical reaction between solid magnesium (Mg) and oxygen gas (O₂), we determine the element being oxidized by examining the change in oxidation states during the reaction. The balanced chemical equation for the reaction is:
2Mg (s) + O₂(g) → 2MgO (s)
Magnesium starts with an oxidation state of 0 in its elemental form and is oxidized to an oxidation state of +2 in magnesium oxide (MgO). Oxygen starts with an oxidation state of 0 in diatomic O₂ and is reduced to an oxidation state of -2 in MgO. The substance being oxidized is Mg(s), as it loses electrons (oxidation is defined as the loss of electrons). Conversely, the oxygen gas O₂ is reducing, as it is the species in the reaction that gains electrons.
Therefore, the element in the species that is oxidized is Mg(s).
The correct option is: B) Mg(s)