1. States of Matter. The Atom and the Periodic Table
1.8. Redox Reactions
Text
Formation of table salt
Ordinary table salt, sodium chloride (NaCl), may be formed when sodium reacts with chlorine gas.
A sodium atom is oxidized
When a sodium atom is oxidized, it gives off an electron and turns into a sodium ion, Na+.
Energy is required to remove the valence electron from the sodium atom.
- A sodium ion, Na+, is formed, as an electron is released.
- The sodium atom now has eight valence electrons (noble gas configuration), which is particularly stable.
A chlorine atom is reduced
When a chlorine atom is reduced, it takes up an electron and turns into a chloride ion, Cl–.
Energy is released when a chlorine takes up an extra electron.
- A chloride ion, Cl–, is formed.
- The chloride ion now has eight valence electrons (noble gas configuration), which is particularly stable.
A redox reaction
With words:
- Sodium + chlorine gas → sodium chloride
With Lewis structures:
-
When sodium is oxidized by chlorine, both ions that form get eight valence electrons (noble gas configurations).
With electron configurations:
-
K L M K L M K L M K L M 11p+ 2e– 8e– 1e– + 17p+ 2e– 8e– 7e– → 11p+ 2e– 8e– 0 + 17p+ 2e– 8e– 8e– sodium atom, Na chlorine atom, Cl sodium ion, Na+ chlorine ion, Cl–
Oxidation + reduction = redox reaction
We can combine the oxidation reaction and the reduction reaction to a redox reaction by adding the two together.
Oxidation: | Na → Na+ + e– | ×2 | |
+ | Reduction: | Cl2 + 2e– → 2Cl– | |
Redox: | 2Na + Cl2 → 2NaCl |
Chlorine gas consists of chlorine molecules, Cl2. Because there are two chlorine atoms in each chlorine molecule, two electrons are taken up by each chlorine molecule. Because of this, the oxidation reaction must be taken ×2 before we can add the reactions together.
- The two e– that are given off in the oxidation reaction are taken up in the reduction. Because of this, we don't need to write them in the redox reaction formula.
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Contents
- 1. States of Matter. The Atom and the Periodic Table
- 1.1. Matter. States of Matter
- 1.2. Elements and Chemical Compounds. Pure Substances and Mixtures
- 1.3. The Birth of Chemistry
- 1.4. Atomic Theory. The Atomic Model
- 1.5. Atomic Number, Mass Number, and Atomic Mass
- 1.6. Electron Configurations
- 1.7. Beyond Bohr's Atomic Model
- 1.8. Redox Reactions
- 1.9. The Structure of the Periodic Table
- 1.10. The Noble Gases
- 1.11. The Alkali Metals and the Halogens
- 1.12. The Alkaline Earth Metals and the Oxygen Group
- 1.13. A Few of the Elements in Group 13, 14, and 15
- 2. Chemical Calculations
- 2.1. Physical Quantity, Magnitude, and Units
- 2.2. Atomic Mass, Molecular Mass, and Unit Mass
- 2.3. Amount of Substance, Molar Mass, and Mass
- 2.4. Stoichiometry. Conservation of mass
- 2.5. Water of Crystallization
- 2.6. Calculating the Formula of a Chemical Compound
- 2.7. From Empirical to Molecular Formulas
- 2.8. Equivalent Amounts of Substance and Masses
- 2.9. Gases and Pressure
- 2.10. Concentrations
- 2.11. Dilutions
- 2.12. Yield
- 2.13. Limiting Reactants
- 3. Chemical Bonding
- 3.1. How Ionic Compounds are Formed
- 3.2. Precipitations
- 3.3. Names and Formulas of Ionic Compounds
- 3.4. Ionic Bonds
- 3.5. Properties of Ionic Compounds
- 3.6. Metal Bonding
- 3.7. Covalent Bonds
- 3.8. Polar Covalent Bonding
- 3.9. Dipoles. Polar and non-polar Molecules
- 3.10. The VSEPR Theory
- 3.11. Hydrogen Bonding. The Peculiar Water
- 3.12. Equals Solves Equal
- 3.13. Solubility of Gases in Water
- 3.14. Solubility of Salts in Water
- 4. Thermochemistry
- 5. Chemical Equilibrium
- 5.1. Reaction Rates
- 5.2. The Law of Mass Action
- 5.3. Calculations on Chemical Equilibrium
- 5.4. Heterogenous Equilibria. Solubility Product
- 5.5. Is the System at Equilibrium? The Reaction Quotient Q
- 5.6. Changing the Concentrations in a System in Equilibrium.
- 5.7. Diluting or Compressing Systems in Equilibrium, or Changing the Temperature
- 6. Acids and bases
- 7. Oxidation and Reduction
- 8. Electrochemistry
- 9. Organic Chemistry
- 9.1. Alkanes
- 9.2. Chain Isomers. Nomenclature
- 9.3. Haloalkanes
- 9.4. Nucleophilic Substitution
- 9.5. Alkenes
- 9.6. Electrophilic Addition. Markovnikov’s Rule
- 9.7. Elimination
- 9.8. Alkynes
- 9.9. Arenes and Aromatic Compounds
- 9.10. Alcohols
- 9.11. Oxidation of Alcohols
- 9.12. Aldehydes and Ketones
- 9.13. Thiols and Disulfides
- 9.14. Ethers
- 9.15. Amines
- 9.16. Nitro Compounds and Organic Nitrates
- 9.17. Carboxylic Acids
- 9.18. More on Carboxylic Acids
- 9.19. Stereoisomerism
- 9.20. Esters
- 9.21. Lipids
- 9.22. Mono-, Oligo-, and Polysaccharides
- 9.23. Amino Acids
- 9.24. Nucleotides
- 10. Biochemistry
- 10.1. Proteins
- 10.2. Enzymes
- 10.3. Catabolic Processes
- 10.4. Carrier Molecules
- 10.5. Glycolysis
- 10.6. Beta-oxidation
- 10.7. The Citric Acid Cycle
- 10.8. The Metabolism of Amino Acids
- 10.9. The Electron Transport Chain
- 10.10. Anabolic Processes
- 10.11. Gluconeogenesis and Fatty Acid Synthesis
- 10.12. DNA: Structure and Function
- 11. Analytical chemistry