Oxidation Rules Review:
1. The oxidation number of an atom in an elemental substance is zero.
2. The oxidation number of a monatomic ion is equal to the ion's charge.
3. Oxidation numbers for common nonmetals are usually assigned as follows:
• Hydrogen: +1 when combined with nonmetals, -1 when combined with metals
• Oxygen: -2 in most compounds, sometimes -1 (so-called peroxides, 0,2^2-), very rarely - 1/2 (so-called
superoxides, 02^-), positive values when combined with F (values vary)
• Halogens: -1 for F always, -1 for other halogens except when combined with oxygen or other halogens (positive oxidation numbers in these cases, varying values)
4. The sum of oxidation numbers for all atoms in a molecule or polyatomic ion equals the charge on the molecule or ion.
Fill out these please:
First Reaction: 2Sr + O2 —-> 2SrO
Oxidized Element:
Reduced Element:
Oxidizing Agent:
Reduction Agent:
____________________________________
Second Reaction: 2Cs+Br2 —-> 2CsBr
Oxidized Element:
Reduced Element:
Oxidizing Agent:
Reduction Agent:
____________________________________
Third Reaction: 2Li + S —-> Li2S
Oxidized Element:
Reduced Element:
Oxidizing Agent:
Reduction Agent:
____________________________________
Fourth Reaction: 2Na+2H2O—->2NaOH+H2
Oxidized Element:
Reduced Element:
Oxidizing Agent:
Reduction Agent:
____________________________________
Fifth Reaction: Mg+2HCI—-> MgCl2+H2
Oxidized Element:
Reduced Element:
Oxidizing Agent:
Reduction Agent:
First Reaction: 2Sr + O2 —-> 2SrO
Oxidized Element: Sr
Reduced Element: O
Oxidizing Agent: O2
Reduction Agent: Sr
Second Reaction: 2Cs+Br2 —-> 2CsBr
Oxidized Element: Br
Reduced Element: Cs
Oxidizing Agent: Cs
Reduction Agent: Br2
Third Reaction: 2Li + S —-> Li2S
Oxidized Element: Li
Reduced Element: S
Oxidizing Agent: S
Reduction Agent: Li
Fourth Reaction: 2Na+2H2O—->2NaOH+H2
Oxidized Element: Na
Reduced Element: H
Oxidizing Agent: H2O
Reduction Agent: Na
Fifth Reaction: Mg+2HCl—-> MgCl2+H2
Oxidized Element: Mg
Reduced Element: H
Oxidizing Agent: HCl
Reduction Agent: Mg