Assign oxidation states to each atom in each element, ion, or compound. Ag, Ca²⁺, BaO, H₂S, NO₃^-, CrO₄^2-

Verified step by step guidance

1. Identify the oxidation state of Ag: Since Ag is a pure element, its oxidation state is 0.
2. Determine the oxidation state of Ca in Ca^{2+}: The oxidation state of Ca in this ion is +2, as indicated by the charge.
3. Assign oxidation states in BaO: Ba is in Group 2, so it has an oxidation state of +2. O is typically -2 in compounds, so it is -2 here.
4. Assign oxidation states in H2S: H is usually +1, so each H is +1. S must balance the total to 0, so S is -2.
5. Determine oxidation states in NO3^{-}: O is -2, and there are three O atoms, totaling -6. The overall charge is -1, so N must be +5 to balance the charge.

Key Concepts

Oxidation States

Oxidation states, or oxidation numbers, are a way to keep track of electrons in chemical compounds. They indicate the degree of oxidation of an atom in a substance, helping to determine how electrons are transferred in redox reactions. The oxidation state of an atom can be positive, negative, or zero, depending on its electron gain or loss relative to its elemental form.

Rules for Assigning Oxidation States

There are specific rules for assigning oxidation states, such as: the oxidation state of an element in its standard state is zero; for monoatomic ions, the oxidation state equals the charge; oxygen typically has an oxidation state of -2, and hydrogen is usually +1. These rules provide a systematic approach to determine the oxidation states in various compounds and ions.

Common Oxidation States of Elements

Different elements have common oxidation states that are frequently encountered in compounds. For example, alkali metals (like sodium) typically have an oxidation state of +1, while alkaline earth metals (like calcium) usually have +2. Transition metals can have multiple oxidation states, which can complicate their assignment in compounds, making familiarity with these common states essential for accurate analysis.