What is an Atom and How Do We Know?

Introduction

• Atoms: fundamental building blocks of chemistry
• Matter is made up of different types of atoms (elements)
• 118 kinds of atoms discovered, listed on the periodic table
• Everything is made of atoms, but they are too small to see with the naked eye
• Curiosity about the existence of atoms leads to exploration

Historical Background

Democritus (Ancient Greece)

• Proposed the idea of an atom (atomos) meaning uncuttable
• Particles are indivisible and indestructible
• No evidence to back the claim originally, many rejected the concept

Arabic World

• Advanced extraction techniques: filtration, boiling, vapor collection, and cooling
• Discovery of pure substances, consistent all the way through

Antoine and Marie-Anne Lavoisier (1700s)

• Studied chemical reactions and element properties
• Could not reduce elements like hydrogen or oxygen further, termed them elements
• Led to listing of elements on the periodic table

Chemical Reactions and Compounds

• Elements react to form compounds with different properties
• Reactions are reversible, elements are conserved
• Examples: Rust (Iron + Oxygen), Water (Hydrogen + Oxygen)

Development of Atomic Theory

John Dalton (Early 1800s)

• Studied patterns in chemical reactions
• Found elements react in whole number ratios
• Suggested atoms of elements are identical in size but different across elements
• Published a book with atomic theory and illustrations

Albert Einstein (1905)

• Proposed an experiment confirming the existence of atoms
• Jean Perrin used Einstein’s concept to determine atomic sizes

Modern Observations

Scanning Tunneling Microscope (1970s)

• Developed by Gerd Binnig and Heinrich Rohrer
• Uses electron tunneling to scan surfaces of samples
• Provided images of silicon atoms

Improved Techniques

• Enhanced presentations of atomic data
• Use of light to visualize atoms by Dr. Ara Apkarian’s team
• Produced images of single nitrogen atoms, confirming atomic theory

Conclusion

• Atoms proven to exist through chemical reactions, mathematical equations, and modern technology
• Atoms can be observed with advanced techniques like scanning tunneling microscopes
• Atom means uncuttable, but they can be split into smaller parts
• Continuation in the series on the fundamentals of chemistry

About the Animation

• Funded by the Casal Research Center (Chemistry at the Space-time Limit) and patrons on Patreon
• Mention of the educational video game “Bond Breaker”