Assign oxidation states to each atom in each element, ion, or compound.
a. Ag b. Ag+ c. CaF2 d. H2S e. CO3 2- f. CrO4 2-
The correct answer and explanation is:
Here is the breakdown of the oxidation states for each atom in the given elements, ions, or compounds:
a. Ag (Silver)
The oxidation state of silver in its elemental form is 0, because pure silver is not combined with any other element.
b. Ag⁺ (Silver ion)
In the silver ion (Ag⁺), the oxidation state of silver is +1. This is because the ion has lost one electron, resulting in a positive charge.
c. CaF₂ (Calcium fluoride)
- Ca (Calcium) has an oxidation state of +2. Calcium is an alkaline earth metal, and elements in this group typically form ions with a charge of +2.
- F (Fluorine) has an oxidation state of -1. Fluorine is a halogen, and it typically has an oxidation state of -1 in its compounds.
d. H₂S (Hydrogen sulfide)
- H (Hydrogen) has an oxidation state of +1. Hydrogen generally has an oxidation state of +1 when bonded to non-metals.
- S (Sulfur) has an oxidation state of -2. In hydrogen sulfide, sulfur typically has an oxidation state of -2, as it is more electronegative than hydrogen.
e. CO₃²⁻ (Carbonate ion)
- C (Carbon) has an oxidation state of +4. In the carbonate ion, carbon is bonded to three oxygen atoms, and the overall charge is -2. Therefore, carbon must have a +4 oxidation state to balance the charges from the oxygen atoms.
- O (Oxygen) has an oxidation state of -2. Oxygen in most compounds, except peroxides, typically has an oxidation state of -2.
f. CrO₄²⁻ (Chromate ion)
- Cr (Chromium) has an oxidation state of +6. In the chromate ion, the overall charge is -2, and the four oxygen atoms contribute a total of -8. To balance this, chromium must have an oxidation state of +6.
- O (Oxygen) has an oxidation state of -2. Each oxygen atom in the chromate ion has an oxidation state of -2.
Each oxidation state is assigned based on the general rules for oxidation numbers, such as the rule that the sum of oxidation states in a neutral compound is zero, and in a polyatomic ion, it equals the ion’s charge.