This is the correct answer because you need equal Iron(Fe) on both sides. Since you already have 2 Irons on the products(right side) side you need 2 on the reactants(left side) side, so you add a 2. For Oxygen(O) since you already have 3 on the products(right) side and only 2 on the reactants(left) side you need to balance those and make them both 6 so you multiply by 2 on the products(right) side and multiply by 3 on the reactants(left) side. Since you can’t add a coefficient to only one element you need to add a 2 to both elements on the product side. So that gets you 4 Iron and 6 Oxygen. On the reactants side you only have 1 Iron and 2 Oxygen. We balance this equation by multiplying by 4 for Iron on the reactants side and multiplying by 3 for Oxygen on the reactants side. So this gets you 4Fe + 3O2 —> 2Fe2O3 I hope this helped!!
Your answer is C forms of the same element that differ in the number of neutrons in each atom because if the number of neutrons change the whole element changes.
As it is located at 7s ^2 it will have 2 valence electrons that due to its position in the s orbital it will be prone to losing them to obtain a noble gas configuration.
