The Mystery of Matter: Search for the Elements

Introduction

• Discussion on the discovery of oxygen and how it catalyzed the search for new elements.
• The role of new tools like batteries in advancing the discovery of elements.

Flame Test and Spectroscope

• Flame test: an old method for identifying elements by color emission.
• Limitation: Similar colors made it hard to differentiate elements.
• Robert Bunsen and Gustav Kirchhoff developed the spectroscope.
  • Utilized Bunsen burner.
  • The spectroscope splits light into a spectrum, showing distinct lines for each element.
  • Like a unique barcode for elements.

Discovery of New Elements

• Spectroscope's role in discovering cesium, rubidium, thallium, indium, and helium.
• 19th-century challenge: No order among newly discovered elements.

Dmitry Mendeleev and the Periodic Table

• Mendeleev’s background and journey from Siberia to St. Petersburg.
• Developed the periodic table in 1869 while writing a textbook.
• Organized elements by atomic weight and similar chemical properties.
• Faced challenges like classifying iodine and tellurium.
• Left spaces for undiscovered elements and predicted their properties.
• Mendeleev's periodic law: Properties of elements vary periodically with atomic weight.

Discovery of Noble Gases

• Discovery of argon and helium challenged the periodic table.
• Addition of noble gases column strengthened the periodic system.

Marie Curie and Radioactivity

• Marie Skłodowska Curie's background, migration to Paris, and education.
• Collaborative work with Pierre Curie on studying uranic rays and radioactivity.
• Discovery of polonium and radium:
  • Radium's intense radioactivity led to further investigation.
• Isolation of radium confirmed by spectral lines and weight measurement.

Curie's Contributions and Legacy

• Marie's struggle for recognition in a male-dominated field.
• Nobel Prize awarded to the Curies and Henri Becquerel.
• Marie Curie’s perseverance and impact on the scientific community.
• Radioactivity's significance: Atoms could split, releasing energy, revealing subatomic structures.

Conclusion

• The periodic table’s evolution and its role in organizing chemical elements.
• Marie Curie’s enduring legacy as a role model for perseverance and scientific exploration.